<PAGE>

    As filed with the Securities and Exchange Commission on January 20, 2000
                                                       Registration No.
--------------------------------------------------------------------------------

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                             ----------------------
                                    FORM S-8
             REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933

                             ----------------------
                                   ECOLAB INC.
             (Exact name of registrant as specified in its charter)

           DELAWARE                                     41-0231510
  (State or other jurisdiction of                    (I.R.S. Employer
   incorporation or organization)                    Identification No.)

                             ----------------------
                                  Ecolab Center
                            370 North Wabasha Street
                            St. Paul, Minnesota 55102
                                 (651) 293-2233
               (Address, including zip code, and telephone number,
            including area code, of registrant's principal executive
                                    offices)

                             ----------------------
                               ECOLAB SAVINGS PLAN
                            (Full title of the plan)

                             ----------------------
                               KENNETH A. IVERSON
                          VICE PRESIDENT AND SECRETARY
                                   ECOLAB INC.
                                  ECOLAB CENTER
                            370 NORTH WABASHA STREET
                            ST. PAUL, MINNESOTA 55102
                                 (651) 293-2125
              (Name and address, including zip code, and telephone
               number, including area code, of agent for service)

                             ----------------------
        APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC:
           IMMEDIATELY UPON THE FILING OF THIS REGISTRATION STATEMENT

                             ----------------------
                         CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>
-----------------------------------------------------------------------------------------------------------------------------------
TITLE OF SECURITIES TO BE         AMOUNT TO BE           PROPOSED MAXIMUM              PROPOSED MAXIMUM            AMOUNT OF
     REGISTERED                   REGISTERED (1)      OFFERING PRICE PER SHARE(2)   AGGREGATE OFFERING PRICE(2)  REGISTRATION FEE
---------------------------- ----------------------- ----------------------------- ---------------------------- -------------------
<S>                              <C>                  <C>                           <C>                          <C>
Common Stock, par value
$1.00 per share (3) .......      2,800,000 shares              $38.78125                  $108,587,500.00            $28,667.10
-----------------------------------------------------------------------------------------------------------------------------------
</TABLE>

(1)      In addition, pursuant to Rule 416(c) under the Securities Act of 1933,
         as amended, this Registration Statement also covers an indeterminate
         amount of interests to be offered or sold pursuant to the employee
         benefit plan described herein.

(2)      Estimated solely for the purpose of calculating the amount of the
         registration fee pursuant to Rule 457(h) under the Securities Act of
         1933, as amended (the "Securities Act"), on the basis of the average
         between the high and low reported sale prices of the Registrant's
         Common Stock on January 18, 2000 as reported on the New York Stock
         Exchange.

(3)      Each share of Common Stock includes one-half share of an associated
         preferred stock purchase right (a "Right").
--------------------------------------------------------------------------------
<PAGE>

                                     PART II

                              INFORMATION REQUIRED
                          IN THE REGISTRATION STATEMENT

ITEM 3. INCORPORATION OF DOCUMENTS BY REFERENCE.

The following documents filed by Ecolab Inc. (the "Company" or the "Registrant")
(File No. 1-9328) or the Ecolab Savings Plan (the "Plan") with the Securities
and Exchange Commission (the "Commission") are incorporated by reference in this
Registration Statement: (1) the Company's Annual Report on Form 10-K for the
year ended December 31, 1998; (2) the Plan's Annual Report on Form 11-K for the
year ended December 31, 1998; (3) the Company's Quarterly Reports on Form 10-Q
for the periods ended March 31, June 30 and September 30, 1999; (4) the
Company's Current Report on Form 8-K dated March 25, 1999; (5) all other reports
filed by the Company pursuant to Sections 13(a) or 15(d) of the Securities
Exchange Act of 1934, as amended (the "Exchange Act"), since December 31, 1998;
and (6) the descriptions of the Company's Common Stock, Preferred Stock and
Rights contained in its Registration Statements on Form 8-A, including any
amendments or reports filed for the purpose of updating such descriptions.

         All documents filed by the Company with the Commission pursuant to
Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act after the date of this
Registration Statement and prior to the filing of a post-effective amendment
which indicates that all shares of Common Stock offered pursuant to this
Registration Statement have been sold or that de-registers all shares of Common
Stock then remaining unsold, shall be deemed to be incorporated by reference in
this Registration Statement and to be a part hereof from the date of filing of
such documents.

         The consolidated financial statements and related financial statement
schedule of the Company, which are included or incorporated by reference in the
Company's Annual Report on Form 10-K for the year ended December 31, 1998, and
incorporated by reference in this Registration Statement, have been audited by
PricewaterhouseCoopers LLP, independent accountants, for the periods indicated
in such firm's reports thereon. The consolidated financial statements and
financial statement schedule audited by PricewaterhouseCoopers LLP have been
incorporated herein by reference in reliance on such firm's reports given upon
their authority as experts in accounting and auditing. To the extent that
PricewaterhouseCoopers LLP examines and reports on the financial statements and
financial statement schedules of the Company issued at future dates, and
consents to the use of their reports thereon, such financial statements and
financial statement schedules will also be incorporated by reference in this
Registration Statement in reliance upon their reports and said authority.

         In addition, the financial statements of the Plan, which are included
in the Plan's Annual Report on Form 11-K for the year ended December 31, 1998,
and incorporated by reference in this Registration Statement, have been audited
by PricewaterhouseCoopers LLP, independent accountants, for the periods
indicated in such firm's report thereon. The financial statements audited by
PricewaterhouseCoopers LLP have been incorporated herein by reference in
reliance on such firm's report given upon their authority as experts in
accounting and auditing. To the extent that PricewaterhouseCoopers LLP examines
and reports on the financial statements of the Plan issued at future dates, and
consents to the use of their reports thereon, such financial statements will
also be incorporated by reference in this Registration Statement in reliance
upon their reports and said authority.

         With respect to unaudited interim financial information incorporated by
reference in this Registration


                                       2

<PAGE>

Statement, PricewaterhouseCoopers LLP has reported that they have applied
limited procedures in accordance with professional standards for reviews of such
information. However, their separate reports, incorporated by reference herein,
state that they did not audit and they do not express an opinion on that interim
financial information. Accordingly, the degree of reliance on their reports on
such information should be restricted in light of the limited nature of the
review procedures applied. The independent accountants are not subject to the
liability provisions of Section 11 of the Securities Act for their reports on
the unaudited interim financial information because each such report is not a
"report" or a "part" of the Registration Statement prepared or certified by the
independent accountants within the meaning of Sections 7 and 11 of the
Securities Act.

         In addition, the combined financial statements and related financial
statement schedule of the Henkel-Ecolab Joint Venture as of November 30, 1998
and for the year ended November 30, 1998, which are included in the Company's
Annual Report on Form 10-K for the year ended December 31, 1998, and
incorporated by reference in this Registration Statement, have been audited by
PricewaterhouseCoopers Gesellschaft mit beschrankter Haftung
Wirtschaftsprufungsgesellschaft, independent accountants. The combined financial
statements and related financial statement schedule audited by
PricewaterhouseCoopers Gesellschaft mit beschrankter Haftung
Wirtschaftsprufungsgesellschaft have been incorporated herein by reference in
reliance on such firm's reports given upon their authority as experts in
accounting and auditing. To the extent that PricewaterhouseCoopers Gesellschaft
mit beschrankter Haftung Wirtschaftsprufungsgesellschaft examines and reports on
the financial statements and financial statement schedules of the Henkel-Ecolab
Joint Venture issued at future dates, and consents to the use of their reports
thereon, such financial statements and financial statement schedules will also
be incorporated by reference in this Registration Statement in reliance upon
their reports and said authority.

         In addition, the combined balance sheets of the Henkel-Ecolab Joint
Venture as of November 30, 1997 and 1996, and the related combined statements of
income, equity and cash flows for each of the periods beginning December 1, 1996
and 1995 and ended November 30, 1997 and 1996, respectively, and related
financial statement schedule for the same periods (collectively, the "1996 and
1997 Henkel-Ecolab Joint Venture Financials"), which are included in the
Company's Annual Report on Form 10-K for the year ended December 31, 1998, and
incorporated by reference in this Registration Statement, have been audited by
KPMG Deutsche Treuhand-Gesellschaft Aktiengesellschaft
Wirtschaftsprufungsgesellschaft, independent accountants. The 1996 and 1997
Henkel-Ecolab Joint Venture Financials audited by KPMG Deutsche
Treuhand-Gesellschaft Aktiengesellschaft Wirtschaftsprufungsgesellschaft have
been incorporated herein by reference in reliance on such firm's reports given
upon their authority as experts in accounting and auditing.

ITEM 4. DESCRIPTION OF SECURITIES.

         Not applicable - the Company's Common Stock and Rights to be offered
pursuant to this Registration Statement have been registered under Section 12 of
the Exchange Act as described in Item 3 of this Part II.

ITEM 5. INTERESTS OF NAMED EXPERTS AND COUNSEL.

         Not applicable.

ITEM 6. INDEMNIFICATION OF DIRECTORS AND OFFICERS.

         Subsection (a) of Section 145 of the General Corporation Law of
Delaware ("DGCL") empowers a


                                       3

<PAGE>

corporation to indemnify any person who was or is a party or is threatened to be
made a party to any threatened, pending or completed action, suit or proceeding,
whether civil, criminal, administrative or investigative (other than an action
by or in the right of the corporation), by reason of the fact that such person
is or was a director, officer, employee or agent of the corporation or is or was
serving at the request of the corporation as a director, officer, employee or
agent of another corporation or enterprise, against expenses (including
attorneys' fees), judgments, fines and amounts paid in settlement actually and
reasonably incurred by such person in connection with such action, suit or
proceeding if such person acted in good faith and in a manner such person
reasonably believed to be in or not opposed to the best interests of the
corporation, and with respect to any criminal action or proceeding, had no
reasonable cause to believe such person's conduct was unlawful.

         Subsection (b) of Section 145 empowers a corporation to indemnify any
person who was or is a party or threatened to be made a party to any threatened,
pending or completed action or suit by or in the right of the corporation to
procure a judgment in its favor by reason of the fact that such person acted in
any of the capacities set forth above, against expenses actually and reasonably
incurred by such person in connection with the defense or settlement of such
action or suit if such person acted under similar standards, except that no
indemnification may be made in respect of any claim, issue or matter as to which
such person shall have been adjudged to be liable to the corporation unless and
only to the extent that the Court of Chancery or the court in which such action
or suit was brought shall determine that, despite the adjudication of liability,
such person is fairly and reasonably entitled to indemnity for such expenses
which the court shall deem proper.

         Section 145 further provides that, to the extent a director or officer
of a corporation has been successful in the defense of any action, suit or
proceeding referred to in subsections (a) and (b) or in the defense of any
claim, issue or matter therein, such person shall be indemnified against
expenses (including attorneys' fees) actually and reasonably incurred in
connection therewith; that indemnification provided for by Section 145 shall not
be deemed exclusive of any other rights to which the indemnified party may be
entitled; and that the scope of indemnification extends to directors, officers,
employees or agents of a constituent corporation absorbed in a consolidation or
merger and persons serving in that capacity at the request of the constituent
corporation for another. Section 145 also empowers the corporation to purchase
and maintain insurance on behalf of a director or officer of the corporation
against any liability asserted against or incurred by such person in any such
capacity or arising out of such person's status as such, whether or not the
corporation would have the power to indemnify such person against such
liabilities under Section 145, including liabilities under the Securities Act.

         Article V of the Company's By-Laws provides for indemnification of the
Company's officers and directors to the full extent allowed by the DGCL.

         In addition, Article IV of the Company's Restated Certificate of
Incorporation provides that the Company's directors do not have personal
liability to the Company or its stockholders for monetary damages for any breach
of their fiduciary duty as directors, except (i) for a breach of the duty of
loyalty, (ii) for acts or omissions not in good faith or which involve
intentional misconduct or knowing violation of the law, (iii) for willful or
negligent violations of certain provisions under the DGCL imposing certain
requirements with respect to stock repurchases, redemptions and dividends, or
(iv) for any transaction from which the director derived an improper personal
benefit. Subject to these exceptions, under Article IV, directors do not have
any personal liability to the Company or its stockholders for any violation of
their fiduciary duty.

         The Company has directors and officers liability insurance which
protects each director or officer from certain claims and suits, including
stockholder derivative suits, even where the director may be


                                       4

<PAGE>

determined to not be entitled to indemnification under the DGCL and claims and
suits arising under the Securities Act. The policy may also afford coverage
under circumstances where the facts do not justify a finding that the director
or officer acted in good faith and in a manner that was in or not opposed to the
best interests of the Company.

         The Company has entered into indemnification agreements with each of
its directors (the "Indemnification Agreements"). The Indemnification Agreements
provide for the prompt indemnification "to the fullest extent permitted by law"
and for the prompt advancement of expenses, including attorneys' fees and other
costs, expenses and obligations paid or incurred in connection with
investigating, defending, being a witness or participating in (including on
appeal) any threatened, pending or completed action, suit or proceeding related
to the fact that such director is or was a director, officer, employee, trustee,
agent or fiduciary of the Company or is or was serving at the request of the
Company as a director, officer, employee, trustee, agent or fiduciary of another
corporation, partnership, joint venture, employee benefit plan trust or other
enterprise, or by reason of anything done or not done by a director in any such
capacity. The Indemnification Agreements further provide that the Company has
the burden of proving that a director is not entitled to indemnification in any
particular case.

         The foregoing represents a summary of the general effect of the DGCL,
the Company's By-Laws and Restated Certificate of Incorporation, the Company's
directors and officers liability insurance coverage and the Indemnification
Agreements for purposes of general description only.

ITEM 7. EXEMPTION FROM REGISTRATION CLAIMED.

         Not applicable - no securities are to be re-offered or resold pursuant
to this Registration Statement.

ITEM 8.  EXHIBITS.

4.1      Restated Certificate of Incorporation of the Company (incorporated by
         reference to Exhibit (3) to the Company's Current Report on Form 8-K
         dated October 22, 1997 (File No. 1-9328)).
4.2      Bylaws of the Company, as amended through February 20, 1999
         (incorporated by reference to Exhibit (3)B to the Company's Annual
         Report on Form 10-K for the year ended December 31, 1998 (File No.
         1-9328)).
4.3      Form of Common Stock Certificate (incorporated by reference to Exhibit
         4(B) to the Company's Annual Report on Form 10-K for the year ended
         December 31, 1995 (File No. 1-9328)).
4.4      Rights Agreement, dated as of February 24, 1996, between the Company
         and First Chicago Trust Company of New York, as Rights Agent
         (incorporated by reference to Exhibit 4 to the Company's Current Report
         on Form 8-K dated February 24, 1996 (File No. 1-9328)).
5.1      Opinion and Consent of Kenneth A. Iverson (filed herewith
         electronically).
5.2      Opinion and Consent of Oppenheimer, Wolff and Donnelly (filed herewith
         electronically).
15.1     Letter of PricewaterhouseCoopers LLP regarding unaudited interim
         financial information (filed herewith electronically).
23.1     Consent of PricewaterhouseCoopers LLP (filed herewith electronically).
23.2     Consent of PricewaterhouseCoopers GmbH (filed herewith electronically).
23.3     Consent of KPMG Deutsche Treuhand-Gesellschaft Aktiengesellschaft
         Wirtschaftsprufungsgesellschaft (filed herewith electronically).
24.1     Powers of Attorney (filed herewith electronically).

ITEM 9. UNDERTAKINGS.


                                       5

<PAGE>

(a)      The undersigned Registrant hereby undertakes:

         (1)      To file, during any period in which offers or sales are being
                  made, a post-effective amendment to this registration
                  statement:

                  (i)      To include any prospectus required by Section
                           10(a)(3) of the Securities Act;

                  (ii)     To reflect in the prospectus any facts or events
                           arising after the effective date of the registration
                           statement (or the most recent post-effective
                           amendment thereof) which, individually or in the
                           aggregate, represent a fundamental change in the
                           information set forth in the registration statement.
                           Notwithstanding the foregoing, any increase or
                           decrease in volume of securities offered (if the
                           total dollar value of securities offered would not
                           exceed that which was registered) and any deviation
                           from the low or high end of the estimated maximum
                           offering range may be reflected in the form of
                           prospectus filed with the Commission pursuant to Rule
                           424(b) under the Securities Act if, in the aggregate,
                           the changes in volume and price represent no more
                           than a 20% change in the maximum aggregate offering
                           price set forth in the "Calculation of Registration
                           Fee" table in the effective registration statement;

                  (iii)    To include any material information with respect to
                           the plan of distribution not previously disclosed in
                           the registration statement or any material change to
                           such information in the registration statement;

                  PROVIDED, HOWEVER, that paragraphs (a)(1)(i) and (a)(1)(ii) do
                  not apply if the information required to be included in a
                  post-effective amendment by those paragraphs is contained in
                  periodic reports filed with or furnished to the Commission by
                  the Registrant pursuant to Section 13 or Section 15(d) of the
                  Exchange Act that are incorporated by reference in the
                  registration statement.

         (2)      That, for the purpose of determining any liability under the
                  Securities Act, each such post-effective amendment shall be
                  deemed to be a new registration statement relating to the
                  securities offered therein, and the offering of such
                  securities at that time shall be deemed to be the initial bona
                  fide offering thereof.

         (3)      To remove from registration by means of a post-effective
                  amendment any of the securities being registered which remain
                  unsold at the termination of the offering.

(b)      The undersigned Registrant hereby undertakes that, for purposes of
         determining any liability under the Securities Act, each filing of the
         Registrant's annual report pursuant to Section 13(a) or Section 15(d)
         of the Exchange Act (and, where applicable, each filing of an employee
         benefit plan's annual report pursuant to Section 15(d) of the Exchange
         Act) that is incorporated by reference in the registration statement
         shall be deemed to be a new registration statement relating to the
         securities offered therein, and the offering of such securities at that
         time shall be deemed to be the initial bona fide offering thereof.

(c)      Insofar as indemnification for liabilities arising under the Securities
         Act may be permitted to directors, officers and controlling persons of
         the Registrant, the Registrant has been advised that in


                                       6

<PAGE>

         the opinion of the Commission such indemnification is against public
         policy as expressed in the Securities Act and is, therefore,
         unenforceable. In the event that a claim for indemnification against
         such liabilities (other than the payment by the Registrant of expenses
         incurred or paid by a director, officer or controlling person of the
         Registrant in the successful defense of any action, suit or proceeding)
         is asserted by such director, officer or controlling person in
         connection with the securities being registered, the Registrant will,
         unless in the opinion of its counsel the matter has been settled by
         controlling precedent, submit to a court of appropriate jurisdiction
         the question whether such indemnification by it is against public
         policy as expressed in the Securities Act and will be governed by the
         final adjudication of such issue.


                                       7

<PAGE>

                                   SIGNATURES

THE REGISTRANT. Pursuant to the requirements of the Securities Act of 1933, the
Registrant certifies that it has reasonable grounds to believe that it meets all
of the requirements for filing on Form S-8 and has duly caused this registration
statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of St. Paul, State of Minnesota, on January 20, 2000.


                                   ECOLAB INC.

                                   By:/s/Allan L. Schuman
                                      ----------------------------------
                                      Allan L. Schuman
                                      Chairman of the Board, President and Chief
                                      Executive Officer

         Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed on January 20, 2000 by the following
persons in the capacities indicated.




/s/Allan L. Schuman                           Chairman of the Board, President
----------------------------------------      and Chief Executive Officer
Allan L. Schuman                              (Principal Executive Officer)
                                              and Director



/s/L. White Matthews, III                     Executive Vice President and Chief
----------------------------------------      Officer (Principal Financial
L. White Matthews, III                        Officer) and Director



/s/Steven L. Fritze                           Vice President and Controller
----------------------------------------      (Principal Accounting Officer)
Steven L. Fritze


/s/Kenneth A. Iverson                         Directors
----------------------------------------
Kenneth A. Iverson, as attorney-in-fact
for Les S. Biller, Ruth S. Block, Jerry A.
Grundhofer, James J. Howard,
William L. Jews, Joel W. Johnson,
Jerry W. Levin, Robert L. Lumpkins,
Richard L. Schall, Roland Schulz,
Hugo Uyterhoeven and Albrecht Woeste


Director not signing:  Reuben F. Richards


                                       8

<PAGE>


THE PLAN. Pursuant to the requirements of the Securities Act, the Plan has duly
caused this Registration Statement to be signed on its behalf by the
undersigned, in the City of St. Paul, State of Minnesota, on January 20, 2000.

                                  ECOLAB SAVINGS PLAN

                                  By:/s/Diane A. Wigglesworth
                                     ----------------------------------
                                     Diane A. Wigglesworth
                                     Compensation Vice President, Ecolab Inc.
                                     (Plan Administrator)


                                       9

<PAGE>

                                INDEX TO EXHIBITS

<TABLE>
<CAPTION>

ITEM NO.               DESCRIPTION                                                     METHOD OF FILING
--------               -----------                                                     ----------------
<S>         <C>                                                        <C>
 4.1        Restated Certificate of Incorporation of                   Incorporated by reference to Exhibit (3) to
            the Company...................................             the Company's Current Report on Form 8-K
                                                                       dated October 22, 1997 (File No. 1-9328).

 4.2        Bylaws of the Company, as amended                          Incorporated by reference to Exhibit (3)B
            through February 20, 1999.....................             to the Company's Annual Report on Form 10-K
                                                                       for the year ended December 31 1998 (File
                                                                       No. 1-9328).


 4.3        Form of Common Stock Certificate..............             Incorporated by reference to Exhibit 4(B) to
                                                                       the Company's Annual Report on Form 10-K for
                                                                       the year ended December 31, 1995
                                                                       (File No. 1-9328).

 4.4        Rights Agreement, dated as of February 24, 1996,           Incorporated by reference to Exhibit 4 to
            between the Company and First Chicago Trust                the Company's Current Report on Form 8-K
            Company of New York, as Rights Agent..........             dated February 24, 1996 (File No. 1-9328).

 5.1        Opinion and Consent of Kenneth A. Iverson.                 Filed herewith electronically.

 5.2        Opinion and Consent of Oppenheimer,                        Filed herewith electronically.
            Wolff and Donnelly


15.1        Letter of PricewaterhouseCoopers LLP regarding             Filed herewith electronically.
            unaudited interim financial information.

23.1        Consent of PricewaterhouseCoopers LLP.                     Filed herewith electronically.

23.2        Consent of PricewaterhouseCoopers GmbH.                    Filed herewith electronically.

23.3        Consent of KPMG Deutsche Treuhand -                        Filed herewith electronically.
            Gesellschaft Aktiengesellschaft
            Wirtschaftsprufungsgesellschaft...............

24.1        Powers of Attorney............................             Filed herewith electronically.
</TABLE>


                                       10
[{"type": "S-8", "sequence": "1", "description": "S-8", "secsgml_size_bytes": 30886}]
{"company-data": {"conformed-name": "ECOLAB INC", "cik": "0000031462", "assigned-sic": "2840", "irs-number": "410231510", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-95043", "film-number": "510342"}, "business-address": {"street1": "ECOLAB CTR", "street2": "370 N WABASHA ST", "city": "ST PAUL", "state": "MN", "zip": "55102", "phone": "6122932233"}, "former-company": {"former-conformed-name": "ECONOMICS LABORATORY INC", "date-changed": "19861203"}}
As filed with the Securities and Exchange Commission on January 20, 2000
                                                       Registration No.
--------------------------------------------------------------------------------

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                             ----------------------
                                    FORM S-8
             REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933

                             ----------------------
                                   ECOLAB INC.
             (Exact name of registrant as specified in its charter)

           DELAWARE                                     41-0231510
  (State or other jurisdiction of                    (I.R.S. Employer
   incorporation or organization)                    Identification No.)

                             ----------------------
                                  Ecolab Center
                            370 North Wabasha Street
                            St. Paul, Minnesota 55102
                                 (651) 293-2233
               (Address, including zip code, and telephone number,
            including area code, of registrant's principal executive
                                    offices)

                             ----------------------
                               ECOLAB SAVINGS PLAN
                            (Full title of the plan)

                             ----------------------
                               KENNETH A. IVERSON
                          VICE PRESIDENT AND SECRETARY
                                   ECOLAB INC.
                                  ECOLAB CENTER
                            370 NORTH WABASHA STREET
                            ST. PAUL, MINNESOTA 55102
                                 (651) 293-2125
              (Name and address, including zip code, and telephone
               number, including area code, of agent for service)

                             ----------------------
        APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC:
           IMMEDIATELY UPON THE FILING OF THIS REGISTRATION STATEMENT

                             ----------------------
                         CALCULATION OF REGISTRATION FEE
-----------------------------------------------------------------------------------------------------------------------------------
TITLE OF SECURITIES TO BE         AMOUNT TO BE           PROPOSED MAXIMUM              PROPOSED MAXIMUM            AMOUNT OF
     REGISTERED                   REGISTERED (1)      OFFERING PRICE PER SHARE(2)   AGGREGATE OFFERING PRICE(2)  REGISTRATION FEE
---------------------------- ----------------------- ----------------------------- ---------------------------- -------------------
Common Stock, par value
$1.00 per share (3) .......      2,800,000 shares              $38.78125                  $108,587,500.00            $28,667.10
-----------------------------------------------------------------------------------------------------------------------------------
(1)      In addition, pursuant to Rule 416(c) under the Securities Act of 1933,
         as amended, this Registration Statement also covers an indeterminate
         amount of interests to be offered or sold pursuant to the employee
         benefit plan described herein.

(2)      Estimated solely for the purpose of calculating the amount of the
         registration fee pursuant to Rule 457(h) under the Securities Act of
         1933, as amended (the "Securities Act"), on the basis of the average
         between the high and low reported sale prices of the Registrant's
         Common Stock on January 18, 2000 as reported on the New York Stock
         Exchange.

(3)      Each share of Common Stock includes one-half share of an associated
         preferred stock purchase right (a "Right").
--------------------------------------------------------------------------------
PART II

                              INFORMATION REQUIRED
                          IN THE REGISTRATION STATEMENT

ITEM 3. INCORPORATION OF DOCUMENTS BY REFERENCE.

The following documents filed by Ecolab Inc. (the "Company" or the "Registrant")
(File No. 1-9328) or the Ecolab Savings Plan (the "Plan") with the Securities
and Exchange Commission (the "Commission") are incorporated by reference in this
Registration Statement: (1) the Company's Annual Report on Form 10-K for the
year ended December 31, 1998; (2) the Plan's Annual Report on Form 11-K for the
year ended December 31, 1998; (3) the Company's Quarterly Reports on Form 10-Q
for the periods ended March 31, June 30 and September 30, 1999; (4) the
Company's Current Report on Form 8-K dated March 25, 1999; (5) all other reports
filed by the Company pursuant to Sections 13(a) or 15(d) of the Securities
Exchange Act of 1934, as amended (the "Exchange Act"), since December 31, 1998;
and (6) the descriptions of the Company's Common Stock, Preferred Stock and
Rights contained in its Registration Statements on Form 8-A, including any
amendments or reports filed for the purpose of updating such descriptions.

         All documents filed by the Company with the Commission pursuant to
Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act after the date of this
Registration Statement and prior to the filing of a post-effective amendment
which indicates that all shares of Common Stock offered pursuant to this
Registration Statement have been sold or that de-registers all shares of Common
Stock then remaining unsold, shall be deemed to be incorporated by reference in
this Registration Statement and to be a part hereof from the date of filing of
such documents.

         The consolidated financial statements and related financial statement
schedule of the Company, which are included or incorporated by reference in the
Company's Annual Report on Form 10-K for the year ended December 31, 1998, and
incorporated by reference in this Registration Statement, have been audited by
PricewaterhouseCoopers LLP, independent accountants, for the periods indicated
in such firm's reports thereon. The consolidated financial statements and
financial statement schedule audited by PricewaterhouseCoopers LLP have been
incorporated herein by reference in reliance on such firm's reports given upon
their authority as experts in accounting and auditing. To the extent that
PricewaterhouseCoopers LLP examines and reports on the financial statements and
financial statement schedules of the Company issued at future dates, and
consents to the use of their reports thereon, such financial statements and
financial statement schedules will also be incorporated by reference in this
Registration Statement in reliance upon their reports and said authority.

         In addition, the financial statements of the Plan, which are included
in the Plan's Annual Report on Form 11-K for the year ended December 31, 1998,
and incorporated by reference in this Registration Statement, have been audited
by PricewaterhouseCoopers LLP, independent accountants, for the periods
indicated in such firm's report thereon. The financial statements audited by
PricewaterhouseCoopers LLP have been incorporated herein by reference in
reliance on such firm's report given upon their authority as experts in
accounting and auditing. To the extent that PricewaterhouseCoopers LLP examines
and reports on the financial statements of the Plan issued at future dates, and
consents to the use of their reports thereon, such financial statements will
also be incorporated by reference in this Registration Statement in reliance
upon their reports and said authority.

         With respect to unaudited interim financial information incorporated by
reference in this Registration

                                       2
Statement, PricewaterhouseCoopers LLP has reported that they have applied
limited procedures in accordance with professional standards for reviews of such
information. However, their separate reports, incorporated by reference herein,
state that they did not audit and they do not express an opinion on that interim
financial information. Accordingly, the degree of reliance on their reports on
such information should be restricted in light of the limited nature of the
review procedures applied. The independent accountants are not subject to the
liability provisions of Section 11 of the Securities Act for their reports on
the unaudited interim financial information because each such report is not a
"report" or a "part" of the Registration Statement prepared or certified by the
independent accountants within the meaning of Sections 7 and 11 of the
Securities Act.

         In addition, the combined financial statements and related financial
statement schedule of the Henkel-Ecolab Joint Venture as of November 30, 1998
and for the year ended November 30, 1998, which are included in the Company's
Annual Report on Form 10-K for the year ended December 31, 1998, and
incorporated by reference in this Registration Statement, have been audited by
PricewaterhouseCoopers Gesellschaft mit beschrankter Haftung
Wirtschaftsprufungsgesellschaft, independent accountants. The combined financial
statements and related financial statement schedule audited by
PricewaterhouseCoopers Gesellschaft mit beschrankter Haftung
Wirtschaftsprufungsgesellschaft have been incorporated herein by reference in
reliance on such firm's reports given upon their authority as experts in
accounting and auditing. To the extent that PricewaterhouseCoopers Gesellschaft
mit beschrankter Haftung Wirtschaftsprufungsgesellschaft examines and reports on
the financial statements and financial statement schedules of the Henkel-Ecolab
Joint Venture issued at future dates, and consents to the use of their reports
thereon, such financial statements and financial statement schedules will also
be incorporated by reference in this Registration Statement in reliance upon
their reports and said authority.

         In addition, the combined balance sheets of the Henkel-Ecolab Joint
Venture as of November 30, 1997 and 1996, and the related combined statements of
income, equity and cash flows for each of the periods beginning December 1, 1996
and 1995 and ended November 30, 1997 and 1996, respectively, and related
financial statement schedule for the same periods (collectively, the "1996 and
1997 Henkel-Ecolab Joint Venture Financials"), which are included in the
Company's Annual Report on Form 10-K for the year ended December 31, 1998, and
incorporated by reference in this Registration Statement, have been audited by
KPMG Deutsche Treuhand-Gesellschaft Aktiengesellschaft
Wirtschaftsprufungsgesellschaft, independent accountants. The 1996 and 1997
Henkel-Ecolab Joint Venture Financials audited by KPMG Deutsche
Treuhand-Gesellschaft Aktiengesellschaft Wirtschaftsprufungsgesellschaft have
been incorporated herein by reference in reliance on such firm's reports given
upon their authority as experts in accounting and auditing.

ITEM 4. DESCRIPTION OF SECURITIES.

         Not applicable - the Company's Common Stock and Rights to be offered
pursuant to this Registration Statement have been registered under Section 12 of
the Exchange Act as described in Item 3 of this Part II.

ITEM 5. INTERESTS OF NAMED EXPERTS AND COUNSEL.

         Not applicable.

ITEM 6. INDEMNIFICATION OF DIRECTORS AND OFFICERS.

         Subsection (a) of Section 145 of the General Corporation Law of
Delaware ("DGCL") empowers a

                                       3
corporation to indemnify any person who was or is a party or is threatened to be
made a party to any threatened, pending or completed action, suit or proceeding,
whether civil, criminal, administrative or investigative (other than an action
by or in the right of the corporation), by reason of the fact that such person
is or was a director, officer, employee or agent of the corporation or is or was
serving at the request of the corporation as a director, officer, employee or
agent of another corporation or enterprise, against expenses (including
attorneys' fees), judgments, fines and amounts paid in settlement actually and
reasonably incurred by such person in connection with such action, suit or
proceeding if such person acted in good faith and in a manner such person
reasonably believed to be in or not opposed to the best interests of the
corporation, and with respect to any criminal action or proceeding, had no
reasonable cause to believe such person's conduct was unlawful.

         Subsection (b) of Section 145 empowers a corporation to indemnify any
person who was or is a party or threatened to be made a party to any threatened,
pending or completed action or suit by or in the right of the corporation to
procure a judgment in its favor by reason of the fact that such person acted in
any of the capacities set forth above, against expenses actually and reasonably
incurred by such person in connection with the defense or settlement of such
action or suit if such person acted under similar standards, except that no
indemnification may be made in respect of any claim, issue or matter as to which
such person shall have been adjudged to be liable to the corporation unless and
only to the extent that the Court of Chancery or the court in which such action
or suit was brought shall determine that, despite the adjudication of liability,
such person is fairly and reasonably entitled to indemnity for such expenses
which the court shall deem proper.

         Section 145 further provides that, to the extent a director or officer
of a corporation has been successful in the defense of any action, suit or
proceeding referred to in subsections (a) and (b) or in the defense of any
claim, issue or matter therein, such person shall be indemnified against
expenses (including attorneys' fees) actually and reasonably incurred in
connection therewith; that indemnification provided for by Section 145 shall not
be deemed exclusive of any other rights to which the indemnified party may be
entitled; and that the scope of indemnification extends to directors, officers,
employees or agents of a constituent corporation absorbed in a consolidation or
merger and persons serving in that capacity at the request of the constituent
corporation for another. Section 145 also empowers the corporation to purchase
and maintain insurance on behalf of a director or officer of the corporation
against any liability asserted against or incurred by such person in any such
capacity or arising out of such person's status as such, whether or not the
corporation would have the power to indemnify such person against such
liabilities under Section 145, including liabilities under the Securities Act.

         Article V of the Company's By-Laws provides for indemnification of the
Company's officers and directors to the full extent allowed by the DGCL.

         In addition, Article IV of the Company's Restated Certificate of
Incorporation provides that the Company's directors do not have personal
liability to the Company or its stockholders for monetary damages for any breach
of their fiduciary duty as directors, except (i) for a breach of the duty of
loyalty, (ii) for acts or omissions not in good faith or which involve
intentional misconduct or knowing violation of the law, (iii) for willful or
negligent violations of certain provisions under the DGCL imposing certain
requirements with respect to stock repurchases, redemptions and dividends, or
(iv) for any transaction from which the director derived an improper personal
benefit. Subject to these exceptions, under Article IV, directors do not have
any personal liability to the Company or its stockholders for any violation of
their fiduciary duty.

         The Company has directors and officers liability insurance which
protects each director or officer from certain claims and suits, including
stockholder derivative suits, even where the director may be

                                       4
determined to not be entitled to indemnification under the DGCL and claims and
suits arising under the Securities Act. The policy may also afford coverage
under circumstances where the facts do not justify a finding that the director
or officer acted in good faith and in a manner that was in or not opposed to the
best interests of the Company.

         The Company has entered into indemnification agreements with each of
its directors (the "Indemnification Agreements"). The Indemnification Agreements
provide for the prompt indemnification "to the fullest extent permitted by law"
and for the prompt advancement of expenses, including attorneys' fees and other
costs, expenses and obligations paid or incurred in connection with
investigating, defending, being a witness or participating in (including on
appeal) any threatened, pending or completed action, suit or proceeding related
to the fact that such director is or was a director, officer, employee, trustee,
agent or fiduciary of the Company or is or was serving at the request of the
Company as a director, officer, employee, trustee, agent or fiduciary of another
corporation, partnership, joint venture, employee benefit plan trust or other
enterprise, or by reason of anything done or not done by a director in any such
capacity. The Indemnification Agreements further provide that the Company has
the burden of proving that a director is not entitled to indemnification in any
particular case.

         The foregoing represents a summary of the general effect of the DGCL,
the Company's By-Laws and Restated Certificate of Incorporation, the Company's
directors and officers liability insurance coverage and the Indemnification
Agreements for purposes of general description only.

ITEM 7. EXEMPTION FROM REGISTRATION CLAIMED.

         Not applicable - no securities are to be re-offered or resold pursuant
to this Registration Statement.

ITEM 8.  EXHIBITS.

4.1      Restated Certificate of Incorporation of the Company (incorporated by
         reference to Exhibit (3) to the Company's Current Report on Form 8-K
         dated October 22, 1997 (File No. 1-9328)).
4.2      Bylaws of the Company, as amended through February 20, 1999
         (incorporated by reference to Exhibit (3)B to the Company's Annual
         Report on Form 10-K for the year ended December 31, 1998 (File No.
         1-9328)).
4.3      Form of Common Stock Certificate (incorporated by reference to Exhibit
         4(B) to the Company's Annual Report on Form 10-K for the year ended
         December 31, 1995 (File No. 1-9328)).
4.4      Rights Agreement, dated as of February 24, 1996, between the Company
         and First Chicago Trust Company of New York, as Rights Agent
         (incorporated by reference to Exhibit 4 to the Company's Current Report
         on Form 8-K dated February 24, 1996 (File No. 1-9328)).
5.1      Opinion and Consent of Kenneth A. Iverson (filed herewith
         electronically).
5.2      Opinion and Consent of Oppenheimer, Wolff and Donnelly (filed herewith
         electronically).
15.1     Letter of PricewaterhouseCoopers LLP regarding unaudited interim
         financial information (filed herewith electronically).
23.1     Consent of PricewaterhouseCoopers LLP (filed herewith electronically).
23.2     Consent of PricewaterhouseCoopers GmbH (filed herewith electronically).
23.3     Consent of KPMG Deutsche Treuhand-Gesellschaft Aktiengesellschaft
         Wirtschaftsprufungsgesellschaft (filed herewith electronically).
24.1     Powers of Attorney (filed herewith electronically).

ITEM 9. UNDERTAKINGS.

                                       5
(a)      The undersigned Registrant hereby undertakes:

         (1)      To file, during any period in which offers or sales are being
                  made, a post-effective amendment to this registration
                  statement:

                  (i)      To include any prospectus required by Section
                           10(a)(3) of the Securities Act;

                  (ii)     To reflect in the prospectus any facts or events
                           arising after the effective date of the registration
                           statement (or the most recent post-effective
                           amendment thereof) which, individually or in the
                           aggregate, represent a fundamental change in the
                           information set forth in the registration statement.
                           Notwithstanding the foregoing, any increase or
                           decrease in volume of securities offered (if the
                           total dollar value of securities offered would not
                           exceed that which was registered) and any deviation
                           from the low or high end of the estimated maximum
                           offering range may be reflected in the form of
                           prospectus filed with the Commission pursuant to Rule
                           424(b) under the Securities Act if, in the aggregate,
                           the changes in volume and price represent no more
                           than a 20% change in the maximum aggregate offering
                           price set forth in the "Calculation of Registration
                           Fee" table in the effective registration statement;

                  (iii)    To include any material information with respect to
                           the plan of distribution not previously disclosed in
                           the registration statement or any material change to
                           such information in the registration statement;

                  PROVIDED, HOWEVER, that paragraphs (a)(1)(i) and (a)(1)(ii) do
                  not apply if the information required to be included in a
                  post-effective amendment by those paragraphs is contained in
                  periodic reports filed with or furnished to the Commission by
                  the Registrant pursuant to Section 13 or Section 15(d) of the
                  Exchange Act that are incorporated by reference in the
                  registration statement.

         (2)      That, for the purpose of determining any liability under the
                  Securities Act, each such post-effective amendment shall be
                  deemed to be a new registration statement relating to the
                  securities offered therein, and the offering of such
                  securities at that time shall be deemed to be the initial bona
                  fide offering thereof.

         (3)      To remove from registration by means of a post-effective
                  amendment any of the securities being registered which remain
                  unsold at the termination of the offering.

(b)      The undersigned Registrant hereby undertakes that, for purposes of
         determining any liability under the Securities Act, each filing of the
         Registrant's annual report pursuant to Section 13(a) or Section 15(d)
         of the Exchange Act (and, where applicable, each filing of an employee
         benefit plan's annual report pursuant to Section 15(d) of the Exchange
         Act) that is incorporated by reference in the registration statement
         shall be deemed to be a new registration statement relating to the
         securities offered therein, and the offering of such securities at that
         time shall be deemed to be the initial bona fide offering thereof.

(c)      Insofar as indemnification for liabilities arising under the Securities
         Act may be permitted to directors, officers and controlling persons of
         the Registrant, the Registrant has been advised that in

                                       6
the opinion of the Commission such indemnification is against public
         policy as expressed in the Securities Act and is, therefore,
         unenforceable. In the event that a claim for indemnification against
         such liabilities (other than the payment by the Registrant of expenses
         incurred or paid by a director, officer or controlling person of the
         Registrant in the successful defense of any action, suit or proceeding)
         is asserted by such director, officer or controlling person in
         connection with the securities being registered, the Registrant will,
         unless in the opinion of its counsel the matter has been settled by
         controlling precedent, submit to a court of appropriate jurisdiction
         the question whether such indemnification by it is against public
         policy as expressed in the Securities Act and will be governed by the
         final adjudication of such issue.

                                       7
SIGNATURES

THE REGISTRANT. Pursuant to the requirements of the Securities Act of 1933, the
Registrant certifies that it has reasonable grounds to believe that it meets all
of the requirements for filing on Form S-8 and has duly caused this registration
statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of St. Paul, State of Minnesota, on January 20, 2000.

                                   ECOLAB INC.

                                   By:/s/Allan L. Schuman
                                      ----------------------------------
                                      Allan L. Schuman
                                      Chairman of the Board, President and Chief
                                      Executive Officer

         Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed on January 20, 2000 by the following
persons in the capacities indicated.

/s/Allan L. Schuman                           Chairman of the Board, President
----------------------------------------      and Chief Executive Officer
Allan L. Schuman                              (Principal Executive Officer)
                                              and Director

/s/L. White Matthews, III                     Executive Vice President and Chief
----------------------------------------      Officer (Principal Financial
L. White Matthews, III                        Officer) and Director

/s/Steven L. Fritze                           Vice President and Controller
----------------------------------------      (Principal Accounting Officer)
Steven L. Fritze

/s/Kenneth A. Iverson                         Directors
----------------------------------------
Kenneth A. Iverson, as attorney-in-fact
for Les S. Biller, Ruth S. Block, Jerry A.
Grundhofer, James J. Howard,
William L. Jews, Joel W. Johnson,
Jerry W. Levin, Robert L. Lumpkins,
Richard L. Schall, Roland Schulz,
Hugo Uyterhoeven and Albrecht Woeste

Director not signing:  Reuben F. Richards

                                       8
THE PLAN. Pursuant to the requirements of the Securities Act, the Plan has duly
caused this Registration Statement to be signed on its behalf by the
undersigned, in the City of St. Paul, State of Minnesota, on January 20, 2000.

                                  ECOLAB SAVINGS PLAN

                                  By:/s/Diane A. Wigglesworth
                                     ----------------------------------
                                     Diane A. Wigglesworth
                                     Compensation Vice President, Ecolab Inc.
                                     (Plan Administrator)

                                       9
INDEX TO EXHIBITS
ITEM NO.               DESCRIPTION                                                     METHOD OF FILING
--------               -----------                                                     ----------------
4.1        Restated Certificate of Incorporation of                   Incorporated by reference to Exhibit (3) to
            the Company...................................             the Company's Current Report on Form 8-K
                                                                       dated October 22, 1997 (File No. 1-9328).

 4.2        Bylaws of the Company, as amended                          Incorporated by reference to Exhibit (3)B
            through February 20, 1999.....................             to the Company's Annual Report on Form 10-K
                                                                       for the year ended December 31 1998 (File
                                                                       No. 1-9328).

 4.3        Form of Common Stock Certificate..............             Incorporated by reference to Exhibit 4(B) to
                                                                       the Company's Annual Report on Form 10-K for
                                                                       the year ended December 31, 1995
                                                                       (File No. 1-9328).

 4.4        Rights Agreement, dated as of February 24, 1996,           Incorporated by reference to Exhibit 4 to
            between the Company and First Chicago Trust                the Company's Current Report on Form 8-K
            Company of New York, as Rights Agent..........             dated February 24, 1996 (File No. 1-9328).

 5.1        Opinion and Consent of Kenneth A. Iverson.                 Filed herewith electronically.

 5.2        Opinion and Consent of Oppenheimer,                        Filed herewith electronically.
            Wolff and Donnelly

15.1        Letter of PricewaterhouseCoopers LLP regarding             Filed herewith electronically.
            unaudited interim financial information.

23.1        Consent of PricewaterhouseCoopers LLP.                     Filed herewith electronically.

23.2        Consent of PricewaterhouseCoopers GmbH.                    Filed herewith electronically.

23.3        Consent of KPMG Deutsche Treuhand -                        Filed herewith electronically.
            Gesellschaft Aktiengesellschaft
            Wirtschaftsprufungsgesellschaft...............

24.1        Powers of Attorney............................             Filed herewith electronically.
10