<PAGE>   1
As filed with the Securities and Exchange Commission on November 19, 1999

                                                        Registration No. 333-
--------------------------------------------------------------------------------
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

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

                                   RETEK INC.
               (Exact name of issuer as specified in its charter)

            DELAWARE                                 510392671
(State or other jurisdiction of                   (I.R.S. Employer
 incorporation or organization)                  Identification No.)

                  MIDWEST PLAZA, 801 NICOLLET MALL, 11TH FLOOR
                              MINNEAPOLIS, MN 55402
          (Address of principal executive offices, including zip code)

                      RETEK INC. 1999 EQUITY INCENTIVE PLAN
                  RETEK INC. 1999 EMPLOYEE STOCK PURCHASE PLAN
                   RETEK INC. 1999 DIRECTORS STOCK OPTION PLAN
                            (Full title of the plans)

                                  JOHN BUCHANAN
                      CHAIRMAN AND CHIEF EXECUTIVE OFFICER
                                   RETEK INC.
                  MIDWEST PLAZA, 801 NICOLLET MALL, 11TH FLOOR
                              MINNEAPOLIS, MN 55402
                                 (612) 630-5700
            (Name, address and telephone number of agent for service)


<TABLE>
<CAPTION>
                                      CALCULATION OF REGISTRATION FEE
-------------------------------------------------------------------------------------------------------------------
   Title of securities          Amount to be       Proposed maximum      Proposed maximum           Amount of
     to be registered            registered         offering price           aggregate          registration fee
                                                       per share          offering price
-------------------------------------------------------------------------------------------------------------------
<S>                             <C>                 <C>                  <C>                     <C>
common stock, par value          7,145,400           $10.00 (2)            $71,454,000.00         $   19,864.21
$0.01 per share                  2,954,600           $34.75 (3)           $102,672,350.00         $   28,542.91
                                 ---------                                                        -------------
                         Total: 10,100,000(1)                                               Total:$   48,407.12

</TABLE>

(1)  Includes 9,000,000 shares under the Retek Inc. 1999 Equity Incentive Plan,
     700,000 shares under the Retek Inc. 1999 Employee Stock Purchase Plan and
     400,000 shares under the Retek Inc. 1999 Directors Stock Option Plan.

(2)  Pursuant to Rule 457(h) under the Securities Act of 1933, as amended (the
     "Securities Act"), the proposed maximum offering price per share and the
     proposed maximum aggregate offering price of the 7,145,400 shares subject
     to currently outstanding stock options under the plans are based on the per
     share exercise price of the stock options.

(3)  The proposed maximum offering price of the 2,954,600 shares registered
     hereunder of $34.75 per share and the proposed maximum aggregate offering
     price of $102,672,350 have been estimated solely for the purpose of
     determining the registration fee pursuant to Rule 457(c) and 457(h), on the
     basis of the average of the high and low prices of Retek Inc. Common Stock,
     par value $0.01 per share, reported on the Nasdaq National Market on
     November 18, 1999.



<PAGE>   2
                                     PART I

              INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS


ITEM 1. PLAN INFORMATION.*

ITEM 2. REGISTRANT INFORMATION AND EMPLOYEE PLAN ANNUAL INFORMATION.*




















------------------------
*    Information required by Part I to be contained in the Section 10(a)
     prespectus is omitted from this Registration Statement in accordance with
     Rule 428 under the Securities Act and the "Note" to Part 1 of Form S-8.



                                        2


<PAGE>   3



                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.   INCORPORATION OF DOCUMENTS BY REFERENCE.

          The following documents filed with the Securities and Exchange
Commission (the "Commission"), are incorporated by reference in this
Registration Statement.

          (i)  Retek Inc.'s (the "Registrant") Registration Statement on Form
          S-1, File No. 333-86841; and

          (ii) the description of the common stock contained in the
          Registrant's Registration Statement on Form 8-A, File No. 000-28121
          for registration under Section 12 of the Exchange Act of 1934, as
          amended (the "Exchange Act").

All other documents subsequently filed by the Registrant pursuant to Section
13(a), 13(c), 14 or 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 by reference in this
Registration Statement and to be a part hereof from the date of filing of such
documents.

ITEM 4.   DESCRIPTION OF SECURITIES.

          Not required.

ITEM 5.   INTERESTS OF NAMED EXPERTS AND COUNSEL.

          None.

ITEM 6.   INDEMNIFICATION OF DIRECTORS AND OFFICERS.

          Section 145 of the Delaware General Corporation Law (the "DGCL")
empowers a Delaware corporation to indemnify any persons who are, or are
threatened to be made, parties to any threatened, pending or completed legal
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 or director of such
corporation or is or was serving at the request of such corporation as a
director, officer, employer or agent of another corporation or enterprise. The
indemnity may include expenses (including attorneys' fees), judgements, fines
and amounts paid in settlement actually and reasonably incurred by such person
in connection with such action, suit or proceeding, provided that such officer
or director acted in good faith and in a manner he or she reasonably believed to
be in, or not opposed to, the best interests of the corporation, and, in the
case of criminal proceedings, had no reasonable cause to believe his or her
conduct was illegal. A Delaware corporation may indemnify officers and directors
against expenses (including attorneys' fees) in connection with the defense or
settlement of an action by or in the right of the corporation under the same
conditions, except that no indemnification is permitted without judicial
approval if the officer or director is adjudged to be liable to the corporation.
Where an officer or director is successful on the merits or otherwise in the
defense of any action referred to above, the corporation must indemnify him or
her against expenses which such officer or director actually and reasonably
incurred. The Certificate of Incorporation of the Registrant provides for
indemnification of the officers and directors of the Registrant to the full
extent permitted by applicable law.



                                       3

<PAGE>   4







          In accordance with Delaware law, the Certificate of Incorporation of
the Registrant contains, and the Amended and Restated Certificate of
Incorporation of the Registrant will contain, a provision to limit the personal
liability of directors of the Registrant for violations of their fiduciary duty.
This provision eliminates each director's liability to the Registrant or its
stockholders for monetary damages except (i) for any breach of the director's
duty of loyalty to the Registrant or its stockholders, (ii) for acts or
omissions not in good faith or which involve intentional misconduct or a knowing
violation of law, (iii) under Section 174 of the DGCL, providing for liability
of directors for unlawful payment of dividends or unlawful stock purchases or
redemptions or (iv) for any transaction from which a director derived an
improper personal benefit. The effect of this provision is to eliminate the
personal liability of directors for monetary damages for actions involving a
breach of their fiduciary duty of care, including any such actions involving
gross negligence.

          Pursuant to the underwriting agreement between the Registrant and the
underwriters filed as an exhibit to the Registration Statement on Form S-1, File
No. 333-86841, the underwriters, a party thereto, have agreed to indemnify each
officer and director of the Registrant and each person, if any, who controls the
Registrant within the meaning of the Securities Act, against certain
liabilities, including liabilities under the Securities Act.

ITEM 7.   EXEMPTION FROM REGISTRATION CLAIMED.

          Not applicable.

ITEM 8.   EXHIBITS.

          The following exhibits are filed as part of this Registration
Statement:

Exhibit
No.       Description of Document
-------   -----------------------

4.1       Certificate of Incorporation (incorporated herein by reference to the
          Registrant's Registration Statement on Form S-1, File No. 333-86841).

4.2       By-Laws (incorporated herein by reference to the Registrant's
          Registration Statement on Form S-1, File No. 333-86841).

4.3       Retek Inc. 1999 Equity Incentive Plan, (incorporated herein by
          reference to the Registrant's Registration Statement on Form S-1, File
          No. 333-86841).

4.4       Retek Inc. 1999 Employee Stock Purchase Plan (incorporated herein by
          reference to the Registrant's Registration Statement on Form S-1, File
          No. 333-86841).

4.5       Retek Inc. 1999 Directors Stock Option Plan (incorporated herein by
          reference to the Registrant's Registration Statement on Form S-1, File
          No. 333-86841).

5         Opinion of Shearman & Sterling.

23.1      Consent of PricewaterhouseCoopers LLP.

23.2      Consent of PricewaterhouseCoopers LLP.

23.3      Consent of Shearman & Sterling (contained in Exhibit 5).

24        Power of Attorney (included as part of the signature pages to this
          Registration Statement).




                                       4

<PAGE>   5




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;

          (ii)   To reflect in the prospectus any facts or events
      arising after the effective date of this 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 this
      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 and of the estimated maximum offering range may be
      reflected in the form of prospectus filed with the
      Commission pursuant to Rule 424(b) if, in the aggregate, the
      changes in volume and price represent no more than a 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 plans of distribution not previously disclosed in
      this Registration Statement or any material change to such
      information in the Registration Statement;

provided, however, that the undertakings set forth in paragraph 1(i) and (1)(ii)
above 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
this Registration Statement.

          (2)    That, for the purpose of determining any liabilities 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 this 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 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



                                       5

<PAGE>   6



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.



                                       6

<PAGE>   7





                                   SIGNATURES

          Pursuant to the requirements of the Securities Act, as amended, 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 Minneapolis, State of Minnesota on the 19th day of
November 1999.






                       Retek Inc.



                       By:   /s/ John Buchanan
                          -----------------------------
                       Name:  John Buchanan
                       Title: Chairman, Chief Executive Officer and Director




<PAGE>   8








          KNOW ALL MEN BY THESE PRESENTS that each person whose signature to
this Registration Statement appears below hereby constitutes and appoints each
of John Buchanan, Gregory A. Effertz and Gordon Masson as such person's true and
lawful attorney-in-fact and agent, with full power of substitution and
resubstitution, for such person and in such person's name, place and stead, in
any and all capacities, to sign any and all amendments to the Registration
Statement, including post-effective amendments, and registration statements
filed pursuant to Rule 462 under the Securities Act, and to file the same, with
all exhibits thereto, and other documents in connection therewith, with the
Commission, and does hereby grant unto each said attorney-in-fact and agent full
power and authority to do and perform each and every act and thing requisite and
necessary to be done in and about the premises, as fully to all intents and
purposes as such person might or could do in person, hereby ratifying and
confirming all that each said attorney-in-fact and agent, or any substitute
therefor, may lawfully do or cause to be done by virtue hereof.

          Pursuant to the requirements of the Securities Act, this Registration
Statement has been signed by the following persons in the capacities indicated
as of the 19th day of November, 1999.


        Signature                           Capacity
        ---------                           --------



/s/ John Buchanan               Chairman; Chief Executive Officer; Director
---------------------------
John Buchanan




/s/  Ward Carey                 Director
---------------------------
Ward Carey




/s/  Charles H. Gaylord         Director
----------------------------
Charles H. Gaylord




/s/ Alex Way Hart
----------------------------    Director
Alex Way Hart




/s/  N. Ross Buckenham          Director
-----------------------------
N. Ross Buckenham




/s/  Glen A. Terbeek            Director
-----------------------------
Glen A. Terbeek



/s/ Stephen E. Watson
----------------------------    Director
Stephen E. Watson





<PAGE>   9




/s/ Greg Effertz                Vice President, Finance & Administration,
----------------------------    Chief Financial Officer, Treasurer and Secretary
Greg Effertz



/s/ James Murdy                 Controller
----------------------------
James Murdy




<PAGE>   10



                                  EXHIBIT INDEX



Number             Title of Exhibit
------             ----------------



4.1       Certificate of Incorporation (incorporated herein by reference to the
          Registrant's Registration Statement on Form S-1, File No. 333-86841).

4.2       By-Laws (incorporated herein by reference to the Registrant's
          Registration Statement on Form S-1, File No. 333-86841).

4.3       Retek Inc. 1999 Equity Incentive Plan, (incorporated herein by
          reference to the Registrant's Registration Statement on Form S-1, File
          No. 333-86841).

4.4       Retek Inc. 1999 Employee Stock Purchase Plan (incorporated herein by
          reference to the Registrant's Registration Statement on Form S-1, File
          No. 333-86841).

4.5       Retek Inc. 1999 Directors Stock Option Plan (incorporated herein by
          reference to the Registrant's Registration Statement on Form S-1, File
          No. 333-86841).

5         Opinion of Shearman & Sterling.

23.1      Consent of PricewaterhouseCoopers LLP.

23.2      Consent of PricewaterhouseCoopers LLP.

23.3      Consent of Shearman & Sterling (contained in Exhibit 5).

24        Power of Attorney (included as part of the signature pages to this
          Registration Statement).











                                       10
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{"company-data": {"conformed-name": "RETEK INC", "cik": "0001094360", "assigned-sic": "7372", "irs-number": "510392671"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-91339", "film-number": "99761368"}, "business-address": {"street1": "801 NICOLLET MALL", "city": "MINNEAPOLIS", "state": "MN", "zip": "55402"}, "mail-address": {"street1": "801 NICOLLET MALL", "city": "MINNEAPOLIS", "state": "MN", "zip": "55402"}}
1
As filed with the Securities and Exchange Commission on November 19, 1999

                                                        Registration No. 333-
--------------------------------------------------------------------------------
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

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

                                   RETEK INC.
               (Exact name of issuer as specified in its charter)

            DELAWARE                                 510392671
(State or other jurisdiction of                   (I.R.S. Employer
 incorporation or organization)                  Identification No.)

                  MIDWEST PLAZA, 801 NICOLLET MALL, 11TH FLOOR
                              MINNEAPOLIS, MN 55402
          (Address of principal executive offices, including zip code)

                      RETEK INC. 1999 EQUITY INCENTIVE PLAN
                  RETEK INC. 1999 EMPLOYEE STOCK PURCHASE PLAN
                   RETEK INC. 1999 DIRECTORS STOCK OPTION PLAN
                            (Full title of the plans)

                                  JOHN BUCHANAN
                      CHAIRMAN AND CHIEF EXECUTIVE OFFICER
                                   RETEK INC.
                  MIDWEST PLAZA, 801 NICOLLET MALL, 11TH FLOOR
                              MINNEAPOLIS, MN 55402
                                 (612) 630-5700
            (Name, address and telephone number of agent for service)
CALCULATION OF REGISTRATION FEE
-------------------------------------------------------------------------------------------------------------------
   Title of securities          Amount to be       Proposed maximum      Proposed maximum           Amount of
     to be registered            registered         offering price           aggregate          registration fee
                                                       per share          offering price
-------------------------------------------------------------------------------------------------------------------
common stock, par value          7,145,400           $10.00 (2)            $71,454,000.00         $   19,864.21
$0.01 per share                  2,954,600           $34.75 (3)           $102,672,350.00         $   28,542.91
                                 ---------                                                        -------------
                         Total: 10,100,000(1)                                               Total:$   48,407.12
(1)  Includes 9,000,000 shares under the Retek Inc. 1999 Equity Incentive Plan,
     700,000 shares under the Retek Inc. 1999 Employee Stock Purchase Plan and
     400,000 shares under the Retek Inc. 1999 Directors Stock Option Plan.

(2)  Pursuant to Rule 457(h) under the Securities Act of 1933, as amended (the
     "Securities Act"), the proposed maximum offering price per share and the
     proposed maximum aggregate offering price of the 7,145,400 shares subject
     to currently outstanding stock options under the plans are based on the per
     share exercise price of the stock options.

(3)  The proposed maximum offering price of the 2,954,600 shares registered
     hereunder of $34.75 per share and the proposed maximum aggregate offering
     price of $102,672,350 have been estimated solely for the purpose of
     determining the registration fee pursuant to Rule 457(c) and 457(h), on the
     basis of the average of the high and low prices of Retek Inc. Common Stock,
     par value $0.01 per share, reported on the Nasdaq National Market on
     November 18, 1999.
2
                                     PART I

              INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

ITEM 1. PLAN INFORMATION.*

ITEM 2. REGISTRANT INFORMATION AND EMPLOYEE PLAN ANNUAL INFORMATION.*

------------------------
*    Information required by Part I to be contained in the Section 10(a)
     prespectus is omitted from this Registration Statement in accordance with
     Rule 428 under the Securities Act and the "Note" to Part 1 of Form S-8.

                                        2
3

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.   INCORPORATION OF DOCUMENTS BY REFERENCE.

          The following documents filed with the Securities and Exchange
Commission (the "Commission"), are incorporated by reference in this
Registration Statement.

          (i)  Retek Inc.'s (the "Registrant") Registration Statement on Form
          S-1, File No. 333-86841; and

          (ii) the description of the common stock contained in the
          Registrant's Registration Statement on Form 8-A, File No. 000-28121
          for registration under Section 12 of the Exchange Act of 1934, as
          amended (the "Exchange Act").

All other documents subsequently filed by the Registrant pursuant to Section
13(a), 13(c), 14 or 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 by reference in this
Registration Statement and to be a part hereof from the date of filing of such
documents.

ITEM 4.   DESCRIPTION OF SECURITIES.

          Not required.

ITEM 5.   INTERESTS OF NAMED EXPERTS AND COUNSEL.

          None.

ITEM 6.   INDEMNIFICATION OF DIRECTORS AND OFFICERS.

          Section 145 of the Delaware General Corporation Law (the "DGCL")
empowers a Delaware corporation to indemnify any persons who are, or are
threatened to be made, parties to any threatened, pending or completed legal
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 or director of such
corporation or is or was serving at the request of such corporation as a
director, officer, employer or agent of another corporation or enterprise. The
indemnity may include expenses (including attorneys' fees), judgements, fines
and amounts paid in settlement actually and reasonably incurred by such person
in connection with such action, suit or proceeding, provided that such officer
or director acted in good faith and in a manner he or she reasonably believed to
be in, or not opposed to, the best interests of the corporation, and, in the
case of criminal proceedings, had no reasonable cause to believe his or her
conduct was illegal. A Delaware corporation may indemnify officers and directors
against expenses (including attorneys' fees) in connection with the defense or
settlement of an action by or in the right of the corporation under the same
conditions, except that no indemnification is permitted without judicial
approval if the officer or director is adjudged to be liable to the corporation.
Where an officer or director is successful on the merits or otherwise in the
defense of any action referred to above, the corporation must indemnify him or
her against expenses which such officer or director actually and reasonably
incurred. The Certificate of Incorporation of the Registrant provides for
indemnification of the officers and directors of the Registrant to the full
extent permitted by applicable law.

                                       3
4

          In accordance with Delaware law, the Certificate of Incorporation of
the Registrant contains, and the Amended and Restated Certificate of
Incorporation of the Registrant will contain, a provision to limit the personal
liability of directors of the Registrant for violations of their fiduciary duty.
This provision eliminates each director's liability to the Registrant or its
stockholders for monetary damages except (i) for any breach of the director's
duty of loyalty to the Registrant or its stockholders, (ii) for acts or
omissions not in good faith or which involve intentional misconduct or a knowing
violation of law, (iii) under Section 174 of the DGCL, providing for liability
of directors for unlawful payment of dividends or unlawful stock purchases or
redemptions or (iv) for any transaction from which a director derived an
improper personal benefit. The effect of this provision is to eliminate the
personal liability of directors for monetary damages for actions involving a
breach of their fiduciary duty of care, including any such actions involving
gross negligence.

          Pursuant to the underwriting agreement between the Registrant and the
underwriters filed as an exhibit to the Registration Statement on Form S-1, File
No. 333-86841, the underwriters, a party thereto, have agreed to indemnify each
officer and director of the Registrant and each person, if any, who controls the
Registrant within the meaning of the Securities Act, against certain
liabilities, including liabilities under the Securities Act.

ITEM 7.   EXEMPTION FROM REGISTRATION CLAIMED.

          Not applicable.

ITEM 8.   EXHIBITS.

          The following exhibits are filed as part of this Registration
Statement:

Exhibit
No.       Description of Document
-------   -----------------------

4.1       Certificate of Incorporation (incorporated herein by reference to the
          Registrant's Registration Statement on Form S-1, File No. 333-86841).

4.2       By-Laws (incorporated herein by reference to the Registrant's
          Registration Statement on Form S-1, File No. 333-86841).

4.3       Retek Inc. 1999 Equity Incentive Plan, (incorporated herein by
          reference to the Registrant's Registration Statement on Form S-1, File
          No. 333-86841).

4.4       Retek Inc. 1999 Employee Stock Purchase Plan (incorporated herein by
          reference to the Registrant's Registration Statement on Form S-1, File
          No. 333-86841).

4.5       Retek Inc. 1999 Directors Stock Option Plan (incorporated herein by
          reference to the Registrant's Registration Statement on Form S-1, File
          No. 333-86841).

5         Opinion of Shearman & Sterling.

23.1      Consent of PricewaterhouseCoopers LLP.

23.2      Consent of PricewaterhouseCoopers LLP.

23.3      Consent of Shearman & Sterling (contained in Exhibit 5).

24        Power of Attorney (included as part of the signature pages to this
          Registration Statement).

                                       4
5

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;

          (ii)   To reflect in the prospectus any facts or events
      arising after the effective date of this 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 this
      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 and of the estimated maximum offering range may be
      reflected in the form of prospectus filed with the
      Commission pursuant to Rule 424(b) if, in the aggregate, the
      changes in volume and price represent no more than a 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 plans of distribution not previously disclosed in
      this Registration Statement or any material change to such
      information in the Registration Statement;

provided, however, that the undertakings set forth in paragraph 1(i) and (1)(ii)
above 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
this Registration Statement.

          (2)    That, for the purpose of determining any liabilities 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 this 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 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

                                       5
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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.

                                       6
7

                                   SIGNATURES

          Pursuant to the requirements of the Securities Act, as amended, 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 Minneapolis, State of Minnesota on the 19th day of
November 1999.

                       Retek Inc.

                       By:   /s/ John Buchanan
                          -----------------------------
                       Name:  John Buchanan
                       Title: Chairman, Chief Executive Officer and Director
8

          KNOW ALL MEN BY THESE PRESENTS that each person whose signature to
this Registration Statement appears below hereby constitutes and appoints each
of John Buchanan, Gregory A. Effertz and Gordon Masson as such person's true and
lawful attorney-in-fact and agent, with full power of substitution and
resubstitution, for such person and in such person's name, place and stead, in
any and all capacities, to sign any and all amendments to the Registration
Statement, including post-effective amendments, and registration statements
filed pursuant to Rule 462 under the Securities Act, and to file the same, with
all exhibits thereto, and other documents in connection therewith, with the
Commission, and does hereby grant unto each said attorney-in-fact and agent full
power and authority to do and perform each and every act and thing requisite and
necessary to be done in and about the premises, as fully to all intents and
purposes as such person might or could do in person, hereby ratifying and
confirming all that each said attorney-in-fact and agent, or any substitute
therefor, may lawfully do or cause to be done by virtue hereof.

          Pursuant to the requirements of the Securities Act, this Registration
Statement has been signed by the following persons in the capacities indicated
as of the 19th day of November, 1999.

        Signature                           Capacity
        ---------                           --------

/s/ John Buchanan               Chairman; Chief Executive Officer; Director
---------------------------
John Buchanan

/s/  Ward Carey                 Director
---------------------------
Ward Carey

/s/  Charles H. Gaylord         Director
----------------------------
Charles H. Gaylord

/s/ Alex Way Hart
----------------------------    Director
Alex Way Hart

/s/  N. Ross Buckenham          Director
-----------------------------
N. Ross Buckenham

/s/  Glen A. Terbeek            Director
-----------------------------
Glen A. Terbeek

/s/ Stephen E. Watson
----------------------------    Director
Stephen E. Watson
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/s/ Greg Effertz                Vice President, Finance & Administration,
----------------------------    Chief Financial Officer, Treasurer and Secretary
Greg Effertz

/s/ James Murdy                 Controller
----------------------------
James Murdy
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                                  EXHIBIT INDEX

Number             Title of Exhibit
------             ----------------

4.1       Certificate of Incorporation (incorporated herein by reference to the
          Registrant's Registration Statement on Form S-1, File No. 333-86841).

4.2       By-Laws (incorporated herein by reference to the Registrant's
          Registration Statement on Form S-1, File No. 333-86841).

4.3       Retek Inc. 1999 Equity Incentive Plan, (incorporated herein by
          reference to the Registrant's Registration Statement on Form S-1, File
          No. 333-86841).

4.4       Retek Inc. 1999 Employee Stock Purchase Plan (incorporated herein by
          reference to the Registrant's Registration Statement on Form S-1, File
          No. 333-86841).

4.5       Retek Inc. 1999 Directors Stock Option Plan (incorporated herein by
          reference to the Registrant's Registration Statement on Form S-1, File
          No. 333-86841).

5         Opinion of Shearman & Sterling.

23.1      Consent of PricewaterhouseCoopers LLP.

23.2      Consent of PricewaterhouseCoopers LLP.

23.3      Consent of Shearman & Sterling (contained in Exhibit 5).

24        Power of Attorney (included as part of the signature pages to this
          Registration Statement).

                                       10