<PAGE>



     As filed with the Securities and Exchange Commission on March 21, 2002

                                                    Registration No. 333-_______
--------------------------------------------------------------------------------

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                           --------------------------
                                    FORM S-8

                             REGISTRATION STATEMENT

                                      UNDER

                           THE SECURITIES ACT OF 1933
                           --------------------------

                              MYKROLIS CORPORATION
             (Exact name of registrant as specified in its charter)


            Delaware                                        04-3536767
  (State or other jurisdiction                           (I.R.S. Employer
of incorporation or organization)                       Identification No.)


                 One Patriots Park, Bedford, Massachusetts 01730
          (Address of principal executive offices, including zip code)
                            -------------------------



             Amended and Restated 2001 Employee Stock Purchase Plan
                            (Full title of the plan)
                            -------------------------

                                Peter W. Walcott
                                One Patriots Park
                          Bedford, Massachusetts 01730
                                 (877) 695-7654

                            -------------------------
 (Name, address and telephone number, including area code, of agent for service)

                         CALCULATION OF REGISTRATION FEE

================================================================================
<TABLE>
<S>                           <C>               <C>                       <C>                     <C>
   Title of Each Class of        Amount to be       Proposed Maximum          Proposed Maximum         Amount of
 Securities to be Registered      Registered       Offering Price Per        Aggregate Offering      Registration
                                                        Share(1)                  Price(1)                Fee
------------------------------ ----------------- ------------------------ ------------------------- ----------------
     Common Stock, $.01           1,000,000              $13.03                 $13,030,000            $1,198.76
    par value per share,          shares(2)
  together with the related
Common Stock Purchase Rights
</TABLE>
================================================================================
(1)  Pursuant to Rules 457(c) and 457(h)(1) under the Securities Act of 1933, as
     amended, the proposed maximum offering price per share and the maximum
     aggregate offering price for the shares have been calculated solely for the
     purpose of computing the registration fee on the basis of the average high
     and low prices of the Common Stock as reported by the New York Stock
     Exchange on March 18, 2002.

(2)  In addition, pursuant to Rule 416(a) under the Securities Act of 1933, this
     registration statement also covers such additional shares of Common Stock,
     and related Common Stock Purchase Rights, as may be issued to prevent
     dilution from stock splits, stock dividends and similar transactions.


<PAGE>

                                     PART II
               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3. Incorporation of Documents by Reference.

        Mykrolis Corporation (the "Registrant") hereby incorporates the
        following documents herein by reference:

        (a)  The Registrant's latest annual report on Form 10-K for the fiscal
             year ended December 31, 2001, filed with the Securities and
             Exchange Commission (the "Commission") pursuant to the Securities
             Exchange Act of 1934, as amended (the "Exchange Act"), on
             February 19, 2002.

        (b)  All other reports filed with the Commission pursuant to Section
             13(a) or 15(d) of the Exchange Act subsequent to December 31,
             2001.

        (c)  The description of (i) the Common Stock, $.01 par value per
             share, contained in Item I of the Company's Registration
             Statement on Form 8-A, filed with the Commission pursuant to
             Section 12 of the Exchange Act on July 20, 2001 and (ii) the
             Common Stock Purchase Rights contained in Item I of the Company's
             Registration Statement on Form 8-A, filed with the Commission
             pursuant to Section 12 of the Exchange Act on January 4, 2002.

        All documents subsequently filed by the Registrant pursuant to Sections
13(a), 13(c), 14 and 15(d) of the Exchange Act, prior to the filing of a
post-effective amendment to this Registration Statement that indicates that all
securities offered have been sold or which deregisters all securities then
remaining unsold, shall be deemed to be incorporated herein by reference from
the date of filing of such documents.

Item 4. Description of Securities.

        Not applicable.

Item 5. Interests of Named Experts and Counsel.

        Not applicable.

Item 6. Indemnification of Directors and Officers.

         The Registrant is incorporated under the laws of the State of Delaware.
Section 145 ("Section 145") of the General Corporation Law of the State of
Delaware, as the same exists or may hereafter be amended (the "General
Corporation Law"), inter alia, provides that a Delaware corporation may
indemnify any persons who were, are or are threatened to be made, parties 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 such corporation), by reason of the fact that such person is or was an
officer, director, employee or agent of such corporation, or is or was serving
at the request of such corporation as a director, officer, employee or agent of
another corporation or enterprise. The indemnity may include 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, provided such person acted in good faith and in a manner he
reasonably believed to be in or not opposed to the corporation's best interests
and, with respect to any criminal action or proceeding, had no reasonable cause
to believe that his conduct was illegal.

         Section 145 further authorizes a corporation to purchase and maintain
insurance on behalf of any person who 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 any liability

<PAGE>

asserted against him and incurred by him in any such capacity, arising out of
his status as such, whether or not the corporation would otherwise have the
power to indemnify him under Section 145.

         The Registrant's restated certificate of incorporation provides that
the registrant's directors shall not be liable to the registrant or its
stockholders for monetary damages for breach of fiduciary duty as a director,
except to the extent that the exculpation from liabilities is not permitted
under the General Corporation Law as in effect at the time such liability is
determined. The Registrant's restated certificate of incorporation provides that
the registrant shall indemnify its directors to the full extent permitted by the
laws of the State of Delaware.

         All of the Registrant's directors and officers are covered by insurance
policies maintained by the Registrant against specified liabilities for actions
taken in their capacities as such, including liabilities under the Securities
Act of 1933, as amended. In addition, the Registrant has entered into
indemnification agreements with each of its directors and executive officers
that provide for indemnification and expense advancement to the fullest extent
permitted under the General Corporation Law.

         The master separation and distribution agreement by and between the
Registrant and Millipore Corporation, and entered into in connection with the
separation of the Registrant from Millipore, provides for indemnification by the
Registrant of Millipore and its directors, officers and employees for some
liabilities, including liabilities under the Securities Act.

Item 7. Exemption From Registration Claimed.

        Not applicable.

Item 8. Exhibits.

        Exhibit

         4.1   Amended and Restated 2001 Employee Stock Purchase Plan
               (previously filed as Exhibit 10.6 to the Annual Report on Form
               10-K, No. 001-16611).

         4.2   Restated Certificate of Incorporation of Mykrolis Corporation
               (previously filed as Exhibit 3.1 to the Registration Statement on
               Form S-1, as amended, No. 333-57182).

         4.3   Amended and Restated By-laws of Mykrolis Corporation (previously
               filed as Exhibit 3.2 to the Registration Statement on Form S-1,
               as amended, No. 333-57182).

         4.4   Rights Agreement, dated November 29, 2001, between Mykrolis
               Corporation and EquiServe Trust Company, N.A., as rights agent
               (incorporated herein by reference to Exhibit 99.1 to Current
               Report on Form 8-K of the Company dated December 10, 2001, No.
               011-16611).

         5.1   Opinion of Ropes & Gray.

         23.1 Consent of PricewaterhouseCoopers LLP.

         24.1 Powers of Attorney.

<PAGE>

Item 9. Undertakings.

     (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 of 1933, as amended (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 a prospectus filed with the Commission
                    pursuant to Rule 424(b) if, in the aggregate, the changes in
                    volume and price represent no more than 20 percent 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) above
          shall 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 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 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

<PAGE>

          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 pursuant to the foregoing provisions, or
          otherwise, the Registrant has been advised that in 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.

<PAGE>


                                   SIGNATURES

     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 Town of Bedford, Commonwealth of Massachusetts, on this 21st
day of March, 2002.

                                              MYKROLIS CORPORATION

                                              By:  /s/ C. William Zadel
                                                   -----------------------------
                                              Name:  C. William Zadel
                                              Title: Chief Executive Officer and
                                                     Chairman of the Board

                                     * * * *

     Pursuant to the requirements of the Securities Act of 1933, as amended,
this Registration Statement has been signed by the following persons in the
capacities and on the dates indicated:
<TABLE>
Signature                                            Title                                       Date
---------                                            -----                                       ----
<S>                                              <C>                                          <C>
/s/ C. William Zadel                                 Chairman of the Board                       March 21, 2002
--------------------                                 Chief Executive Officer
C. WILLIAM ZADEL                                     (Principal Executive
                                                     Officer) and Director


/s/ Bertrand Loy                                     Vice President and                          March 21, 2002
---------------------                                Chief Financial Officer
BERTRAND LOY                                         (Principal Financial and
                                                     Accounting Officer)


        *                                            Director                                    March 21, 2002
---------------------
THOMAS O. PYLE

        *                                            Director                                    March 21, 2002
---------------------
ROBERT E. CALDWELL

        *                                            Director                                    March 21, 2002
---------------------
MICHAEL A. BRADLEY

        *                                            Director                                    March 21, 2002
---------------------
MICHAEL P.C. CARNS

        *                                            Director                                    March 21, 2002
---------------------
DANIEL W. CHRISTMAN

                                                     Director
---------------------
RICHARD A. AURELIO
</TABLE>

*    The undersigned, by signing his name hereto, does hereby sign and execute
     this Registration Statement on Form S-8 on behalf of the above named
     directors of the Registrant pursuant to the Power of Attorney executed by
     each such director and filed as Exhibit 24.1 to this Registration Statement
     on Form S-8 on behalf of such directors.

By:/s/ Peter W. Walcott                                           March 21, 2002
   --------------------
    Peter W. Walcott
    Attorney-in-Fact


<PAGE>
                                 EXHIBIT INDEX

4.1  Amended and Restated 2001 Employee Stock Purchase Plan (previously filed as
     Exhibit 10.6 to the Annual Report on Form 10-K, No. 001-16611).

4.2  Restated Certificate of Incorporation of Mykrolis Corporation (previously
     filed as Exhibit 3.1 to the Registration Statement on Form S-1, as amended,
     No. 333-57182).

4.3  Amended and Restated By-laws of Mykrolis Corporation (previously filed as
     Exhibit 3.2 to the Registration Statement on Form S-1, as amended, No.
     333-57182).

4.4  Rights Agreement, dated November 29, 2001, between Mykrolis Corporation and
     EquiServe Trust Company, N.A., as rights agent (incorporated herein by
     reference to Exhibit 99.1 to Current Report on Form 8-K of the Company
     dated December 10, 2001, No. 011-16611).

5.1  Opinion of Ropes & Gray.

23.1 Consent of PricewaterhouseCoopers LLP.

24.1 Powers of Attorney.
[{"type": "S-8", "sequence": "1", "filename": "ds8.txt", "description": "FORM S-8", "secsgml_size_bytes": 19317}]
{"company-data": {"conformed-name": "MYKROLIS CORP", "cik": "0001133082", "assigned-sic": "3826", "irs-number": "043536767", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-84678", "film-number": "02581158"}, "business-address": {"street1": "80 ASHBY ROAD", "city": "BEDFORD", "state": "MA", "zip": "01730", "phone": "8006455476"}, "mail-address": {"street1": "80 ASHBY ROAD", "city": "BEDFORD", "state": "MA", "zip": "01730"}, "former-company": {"former-conformed-name": "MILLIPORE MICROELECTRONICS INC", "date-changed": "20010123"}}
As filed with the Securities and Exchange Commission on March 21, 2002

                                                    Registration No. 333-_______
--------------------------------------------------------------------------------

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                           --------------------------
                                    FORM S-8

                             REGISTRATION STATEMENT

                                      UNDER

                           THE SECURITIES ACT OF 1933
                           --------------------------

                              MYKROLIS CORPORATION
             (Exact name of registrant as specified in its charter)

            Delaware                                        04-3536767
  (State or other jurisdiction                           (I.R.S. Employer
of incorporation or organization)                       Identification No.)

                 One Patriots Park, Bedford, Massachusetts 01730
          (Address of principal executive offices, including zip code)
                            -------------------------

             Amended and Restated 2001 Employee Stock Purchase Plan
                            (Full title of the plan)
                            -------------------------

                                Peter W. Walcott
                                One Patriots Park
                          Bedford, Massachusetts 01730
                                 (877) 695-7654

                            -------------------------
 (Name, address and telephone number, including area code, of agent for service)

                         CALCULATION OF REGISTRATION FEE

================================================================================
Title of Each Class of        Amount to be       Proposed Maximum          Proposed Maximum         Amount of
 Securities to be Registered      Registered       Offering Price Per        Aggregate Offering      Registration
                                                        Share(1)                  Price(1)                Fee
------------------------------ ----------------- ------------------------ ------------------------- ----------------
     Common Stock, $.01           1,000,000              $13.03                 $13,030,000            $1,198.76
    par value per share,          shares(2)
  together with the related
Common Stock Purchase Rights
================================================================================
(1)  Pursuant to Rules 457(c) and 457(h)(1) under the Securities Act of 1933, as
     amended, the proposed maximum offering price per share and the maximum
     aggregate offering price for the shares have been calculated solely for the
     purpose of computing the registration fee on the basis of the average high
     and low prices of the Common Stock as reported by the New York Stock
     Exchange on March 18, 2002.

(2)  In addition, pursuant to Rule 416(a) under the Securities Act of 1933, this
     registration statement also covers such additional shares of Common Stock,
     and related Common Stock Purchase Rights, as may be issued to prevent
     dilution from stock splits, stock dividends and similar transactions.
PART II
               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3. Incorporation of Documents by Reference.

        Mykrolis Corporation (the "Registrant") hereby incorporates the
        following documents herein by reference:

        (a)  The Registrant's latest annual report on Form 10-K for the fiscal
             year ended December 31, 2001, filed with the Securities and
             Exchange Commission (the "Commission") pursuant to the Securities
             Exchange Act of 1934, as amended (the "Exchange Act"), on
             February 19, 2002.

        (b)  All other reports filed with the Commission pursuant to Section
             13(a) or 15(d) of the Exchange Act subsequent to December 31,
             2001.

        (c)  The description of (i) the Common Stock, $.01 par value per
             share, contained in Item I of the Company's Registration
             Statement on Form 8-A, filed with the Commission pursuant to
             Section 12 of the Exchange Act on July 20, 2001 and (ii) the
             Common Stock Purchase Rights contained in Item I of the Company's
             Registration Statement on Form 8-A, filed with the Commission
             pursuant to Section 12 of the Exchange Act on January 4, 2002.

        All documents subsequently filed by the Registrant pursuant to Sections
13(a), 13(c), 14 and 15(d) of the Exchange Act, prior to the filing of a
post-effective amendment to this Registration Statement that indicates that all
securities offered have been sold or which deregisters all securities then
remaining unsold, shall be deemed to be incorporated herein by reference from
the date of filing of such documents.

Item 4. Description of Securities.

        Not applicable.

Item 5. Interests of Named Experts and Counsel.

        Not applicable.

Item 6. Indemnification of Directors and Officers.

         The Registrant is incorporated under the laws of the State of Delaware.
Section 145 ("Section 145") of the General Corporation Law of the State of
Delaware, as the same exists or may hereafter be amended (the "General
Corporation Law"), inter alia, provides that a Delaware corporation may
indemnify any persons who were, are or are threatened to be made, parties 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 such corporation), by reason of the fact that such person is or was an
officer, director, employee or agent of such corporation, or is or was serving
at the request of such corporation as a director, officer, employee or agent of
another corporation or enterprise. The indemnity may include 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, provided such person acted in good faith and in a manner he
reasonably believed to be in or not opposed to the corporation's best interests
and, with respect to any criminal action or proceeding, had no reasonable cause
to believe that his conduct was illegal.

         Section 145 further authorizes a corporation to purchase and maintain
insurance on behalf of any person who 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 any liability
asserted against him and incurred by him in any such capacity, arising out of
his status as such, whether or not the corporation would otherwise have the
power to indemnify him under Section 145.

         The Registrant's restated certificate of incorporation provides that
the registrant's directors shall not be liable to the registrant or its
stockholders for monetary damages for breach of fiduciary duty as a director,
except to the extent that the exculpation from liabilities is not permitted
under the General Corporation Law as in effect at the time such liability is
determined. The Registrant's restated certificate of incorporation provides that
the registrant shall indemnify its directors to the full extent permitted by the
laws of the State of Delaware.

         All of the Registrant's directors and officers are covered by insurance
policies maintained by the Registrant against specified liabilities for actions
taken in their capacities as such, including liabilities under the Securities
Act of 1933, as amended. In addition, the Registrant has entered into
indemnification agreements with each of its directors and executive officers
that provide for indemnification and expense advancement to the fullest extent
permitted under the General Corporation Law.

         The master separation and distribution agreement by and between the
Registrant and Millipore Corporation, and entered into in connection with the
separation of the Registrant from Millipore, provides for indemnification by the
Registrant of Millipore and its directors, officers and employees for some
liabilities, including liabilities under the Securities Act.

Item 7. Exemption From Registration Claimed.

        Not applicable.

Item 8. Exhibits.

        Exhibit

         4.1   Amended and Restated 2001 Employee Stock Purchase Plan
               (previously filed as Exhibit 10.6 to the Annual Report on Form
               10-K, No. 001-16611).

         4.2   Restated Certificate of Incorporation of Mykrolis Corporation
               (previously filed as Exhibit 3.1 to the Registration Statement on
               Form S-1, as amended, No. 333-57182).

         4.3   Amended and Restated By-laws of Mykrolis Corporation (previously
               filed as Exhibit 3.2 to the Registration Statement on Form S-1,
               as amended, No. 333-57182).

         4.4   Rights Agreement, dated November 29, 2001, between Mykrolis
               Corporation and EquiServe Trust Company, N.A., as rights agent
               (incorporated herein by reference to Exhibit 99.1 to Current
               Report on Form 8-K of the Company dated December 10, 2001, No.
               011-16611).

         5.1   Opinion of Ropes & Gray.

         23.1 Consent of PricewaterhouseCoopers LLP.

         24.1 Powers of Attorney.
Item 9. Undertakings.

     (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 of 1933, as amended (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 a prospectus filed with the Commission
                    pursuant to Rule 424(b) if, in the aggregate, the changes in
                    volume and price represent no more than 20 percent 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) above
          shall 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 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 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 pursuant to the foregoing provisions, or
          otherwise, the Registrant has been advised that in 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.
SIGNATURES

     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 Town of Bedford, Commonwealth of Massachusetts, on this 21st
day of March, 2002.

                                              MYKROLIS CORPORATION

                                              By:  /s/ C. William Zadel
                                                   -----------------------------
                                              Name:  C. William Zadel
                                              Title: Chief Executive Officer and
                                                     Chairman of the Board

                                     * * * *

     Pursuant to the requirements of the Securities Act of 1933, as amended,
this Registration Statement has been signed by the following persons in the
capacities and on the dates indicated:

Signature                                            Title                                       Date
---------                                            -----                                       ----
/s/ C. William Zadel                                 Chairman of the Board                       March 21, 2002
--------------------                                 Chief Executive Officer
C. WILLIAM ZADEL                                     (Principal Executive
                                                     Officer) and Director

/s/ Bertrand Loy                                     Vice President and                          March 21, 2002
---------------------                                Chief Financial Officer
BERTRAND LOY                                         (Principal Financial and
                                                     Accounting Officer)

        *                                            Director                                    March 21, 2002
---------------------
THOMAS O. PYLE

        *                                            Director                                    March 21, 2002
---------------------
ROBERT E. CALDWELL

        *                                            Director                                    March 21, 2002
---------------------
MICHAEL A. BRADLEY

        *                                            Director                                    March 21, 2002
---------------------
MICHAEL P.C. CARNS

        *                                            Director                                    March 21, 2002
---------------------
DANIEL W. CHRISTMAN

                                                     Director
---------------------
RICHARD A. AURELIO
*    The undersigned, by signing his name hereto, does hereby sign and execute
     this Registration Statement on Form S-8 on behalf of the above named
     directors of the Registrant pursuant to the Power of Attorney executed by
     each such director and filed as Exhibit 24.1 to this Registration Statement
     on Form S-8 on behalf of such directors.

By:/s/ Peter W. Walcott                                           March 21, 2002
   --------------------
    Peter W. Walcott
    Attorney-in-Fact
EXHIBIT INDEX

4.1  Amended and Restated 2001 Employee Stock Purchase Plan (previously filed as
     Exhibit 10.6 to the Annual Report on Form 10-K, No. 001-16611).

4.2  Restated Certificate of Incorporation of Mykrolis Corporation (previously
     filed as Exhibit 3.1 to the Registration Statement on Form S-1, as amended,
     No. 333-57182).

4.3  Amended and Restated By-laws of Mykrolis Corporation (previously filed as
     Exhibit 3.2 to the Registration Statement on Form S-1, as amended, No.
     333-57182).

4.4  Rights Agreement, dated November 29, 2001, between Mykrolis Corporation and
     EquiServe Trust Company, N.A., as rights agent (incorporated herein by
     reference to Exhibit 99.1 to Current Report on Form 8-K of the Company
     dated December 10, 2001, No. 011-16611).

5.1  Opinion of Ropes & Gray.

23.1 Consent of PricewaterhouseCoopers LLP.

24.1 Powers of Attorney.