<PAGE>

   As filed with the Securities and Exchange Commission on November 19, 1998
                                                      Registration No. 333-
================================================================================
--------------------------------------------------------------------------------

                      SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C. 20549

                               -----------------

                                   FORM S-8

                            REGISTRATION STATEMENT
                                     Under
                          The Securities Act of 1933

                           PLATINUM technology, inc.
            (Exact name of registrant as specified in its charter)

            Delaware                                         36-3509662
 (State or other jurisdiction of                    (IRS Employer Identification
of incorporation or organization)                             Number)

   1815 South Meyers Road, Oakbrook Terrace, Illinois 60181, (630) 620-5000
          (Address of Principal Executive Offices including Zip Code)

            PLATINUM technology, inc. Broad Based Stock Option Plan
                             (Full title of the plan)

                             Andrew J. Filipowski
   1815 South Meyers Road, Oakbrook Terrace, Illinois 60181, (630) 620-5000
           (Name, address and telephone number of agent for service)

                                  Copies to:
                            Matthew S. Brown, Esq.
                              Mark D. Wood, Esq.
                             Katten Muchin & Zavis
                       525 W. Monroe Street, Suite 1600
                            Chicago, IL 60661-3693
                          Fax Number: (312) 902-1061

                               -----------------

<TABLE>
<CAPTION>
                                           CALCULATION OF REGISTRATION FEE
=========================================================================================================================
                                                                   Proposed maximum   Proposed maximum
                                                                    offering price   aggregate offering     Amount of
Title of securities to be registered   Amount to be registered(1)     per share            price         registration fee
-------------------------------------------------------------------------------------------------------------------------
<S>                                    <C>                         <C>               <C>                 <C>
Common Stock, $.001 par value.......     2,403,300 shares(2)          $20.5416(3)      $ 49,367,627(3)       $13,724.20
-------------------------------------------------------------------------------------------------------------------------
Common Stock, $.001 par value.......    12,596,700 shares(4)          $ 16.625(5)      $209,420,138(5)       $58,218.80
-------------------------------------------------------------------------------------------------------------------------
TOTAL                                   15,000,000 shares                              $258,787,765          $71,943.00
=========================================================================================================================
</TABLE>

(1)  Includes an indeterminate number of shares of Common Stock, par value $.001
     per share, of PLATINUM technology, inc. ("PLATINUM Common Stock") that may
     be issuable by reason of stock splits, stock dividends or similar
     transactions. Also includes associated rights (the "Rights") to purchase
     1/100 of a share of Series A Participating Preferred Stock, par value $.01
     per share, of PLATINUM technology, inc. The Rights initially attached to
     and trade with PLATINUM Common Stock. The value attributable to such
     Rights, if any, is reflected in the market price of the PLATINUM Common
     Stock.

(2)  This amount reflects an aggregate of 2,403,300 shares of PLATINUM Common
     Stock issuable upon exercise of outstanding options under the PLATINUM
     technology, inc. Broad Based Stock Option Plan (the "Broad Based Plan")

(3)  Based upon the weighted average exercise price of the shares subject to
     outstanding options under the Broad Based Plan.

(4)  This amount reflects an aggregate of 12,596,700 shares of PLATINUM Common
     Stock which are issuable under the Broad Based Plan.

(5)  Based upon the high and low sales prices of PLATINUM Common Stock, as
     reported on the Nasdaq National Market on November 12, 1998, and used
     solely for the purpose of calculating the registration fee pursuant to Rule
     457 under the Securities Act of 1933.
<PAGE>
 

                                    PART I

                    INFORMATION REQUIRED IN THE PROSPECTUS

     The information called for in Part I of Form S-8 is currently included in
the prospectus for the PLATINUM technology, inc. Broad Based Stock Option Plan
and is not being filed with or included in this Form S-8 in accordance with the
rules and regulations of the Securities and Exchange Commission (the
"Commission").
<PAGE>

                                    PART II
              INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

     Item 3. Incorporation of Documents by Reference.

     The following documents have been filed by the Company with the Commission
under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), and
are incorporated in this Registration Statement by reference:

     1.   The Company's Annual Report on Form 10-K for the year ended December
          31, 1997;

     2.   The Company's Quarterly Reports on Form 10-Q for the quarters ended
          March 31, 1998, June 30, 1998 and September 30, 1998;

     3.   The Company's Current Reports on Form 8-K dated January 27, 1998,
          March 3, 1998, April 16, 1998, April 21, 1998 (as amended by a
          Current Report on Form 8-K/A dated May 6, 1998), May 28, 1998, July
          14, 1998, August 4, 1998, August 13, 1998 and October 15, 1998;

     4.   The description of the Common Stock contained in the Company's
          Registration Statement on Form 8-A filed March 7, 1991 pursuant to
          Section 12 of the Exchange Act and all amendments thereto and reports
          filed for the purpose of updating such description; and

     5.   The description of the Rights contained in the Company's Registration
          Statement on Form 8-A filed December 26, 1995 pursuant to Section 12
          of the Exchange Act and all amendments thereto and reports filed for
          the purpose of updating such description.

     In addition, all documents filed by the Company pursuant to Sections 13(a),
13(c), 14 and 15(d) of the Exchange Act, subsequent to the date hereof and prior
to the filing of a post-effective amendment indicating that all securities
offered pursuant to this Registration Statement have been sold or deregistering
all such securities then remaining unsold, shall be deemed to be incorporated by
reference herein and to be part hereof from the date of filing of such
documents. Any statement contained in a document incorporated or deemed to be
incorporated by reference herein shall be deemed to be modified or superseded
for purposes of this Registration Statement to the extent that a statement
contained herein or in any subsequently filed document which also is or is
deemed to be incorporated by reference herein modifies or supersedes such
statement.

Item 4. Description of Securities.

     Not Applicable. 

Item 5. Interests of Named Experts and Counsel.

     Not Applicable.

Item 6. Indemnification of Directors and Officers.

     Article Ten of the Company's Restated Certificate of Incorporation provides
that the Company shall indemnify its directors to the full extent permitted by
the Delaware General Corporation Law and may indemnify its officers to such
extent, except that the Company shall not be obligated to indemnify any such
person (i) with respect to proceedings, claims or actions initiated or brought
voluntarily by any such person and not by way of defense, or (ii) for any
amounts paid in settlement of an action indemnified against by the Company
without the prior written consent of the Company. With the approval of its
stockholders, the Company has entered into indemnity agreements with each of its
directors and certain of its officers. These agreements may require the Company,
among other things, to indemnify such officers and directors against certain
liabilities that may arise by reason of their status or service as directors or
officers, to advance expenses to them as they are incurred, provided that they
undertake to repay the amount advanced if it is ultimately determined by a court
that they are not entitled to indemnification, and to obtain directors' and
officers' liability insurance if available on reasonable terms.

                                       3
<PAGE>

     In addition, Article Nine of the Company's Restated Certificate of
Incorporation provides that a director of the Company shall not be personally
liable to the Company or its stockholders for monetary damages for breach of his
or her fiduciary duty as a director, except for liability (i) for any breach of
the director's duty of loyalty to the Company 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 General Corporation Law
of the State of Delaware, or (iv) for any transaction from which the director
derives an improper personal benefit.

     Reference is made to Section 145 of the General Corporation Law of the
State of Delaware which provides for indemnification of directors and officers
in certain circumstances.

     The Company has purchased an insurance policy under which it is entitled to
be reimbursed for certain indemnity payments it is required or permitted to make
to its directors and officers.

Item 7. Exemption from Registration Claimed.

     Not Applicable.
<TABLE>
<CAPTION>
Item 8. Exhibits.
<C>          <S>
     4.1     Conformed copy of the Restated Certificate of Incorporation of the
             Company, as amended (incorporated by reference to Exhibit 3.1(d) to
             the Company's Registration Statement on Form S-1, Registration No.
             333-07783).

     4.2     Bylaws of the Company (incorporated by reference to Exhibit 3.2 to
             the Company's Registration Statement on Form S-1, Registration No.
             33-39233 (the "IPO S-1")).

     4.3     Specimen stock certificate representing PLATINUM Common Stock
             (incorporated by reference to Exhibit 4.1 to the IPO S-1).

     4.4     Rights Agreement dated as of December 21, 1995, between the Company
             and Harris Trust and Savings Bank (incorporated by reference to
             Exhibit 1 to the Company's Registration Statement on Form 8-A,
             filed December 26, 1995).

     4.5     PLATINUM technology, inc. Restated Broad Based Stock Option Plan
             (the "Broad Based Plan").

     4.6     Form of Stock Option Agreement under the Broad Based Plan 
             (incorporated by reference to Exhibit 10.4 to the Company's
             Quarterly Report on Form 10-Q for the quarter ended June 30, 1998).

     5       Opinion of counsel as to legality of shares of Common Stock being
             offered (including consent).

     15      Acknowledgment of KPMG Peat Marwick LLP Regarding Independent 
             Auditors' Review Report.

     23.1    Consent of KPMG Peat Marwick LLP with respect to the Company's
             financial statements.

     23.2    Consent of Arthur Andersen LLP with respect to Mastering, Inc.'s
             financial statements.

     23.3    Consent of Ernst & Young LLP with respect to Logic Works, Inc.'s
             financial statements.

     23.4    Consent of Katten Muchin & Zavis (included in their opinion filed
             as Exhibit 5 hereto).

     24      Power of Attorney (included on the signature page of this
             Registration Statement).
</TABLE>

Item 9. Undertakings.

     1. The Company hereby undertakes:

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

                                       4
<PAGE>
 

               (i) To include any prospectus required by Section 10(a)(3) of the
          Securities Act of 1933;

               (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) 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
          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)(i) and (a)(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 Company pursuant to Section 13 or Section 15(d) of the
     Exchange Act that are incorporated by reference in the Registration
     Statement.

          (b) That, for the purpose of determining any liability under the
     Securities Act of 1933, 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.

          (c) 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.

     2. The Company hereby undertakes that, for the purpose of determining any
liability under the Securities Act of 1933, each filing of the Company's annual
report pursuant to Section 13(a) or 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.

     3. Insofar as indemnification for liabilities arising under the Securities
Act of 1933 may be permitted to directors, officers and controlling persons of
the Company and affiliated companies pursuant to the provisions described in
Item 6 above, or otherwise, the Company has been informed that in the opinion of
the Commission such indemnification is against public policy as expressed in the
Securities Act of 1933 and is therefore unenforceable. In the event that a claim
for indemnification against such liabilities (other than the payment by the
Company of expenses incurred or paid by a director, officer or controlling
person of the Company 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 Company 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 of 1933 and will be governed by the final adjudication of such issue.

                                       5
<PAGE>

                                  SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, the Company
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 Oakbrook Terrace, State of Illinois, on this 19th day
of November, 1998.

                                       PLATINUM technology, inc.

                                       By: /s/ ANDREW J. FILIPOWSKI
                                           -------------------------------------
                                           Andrew J. Filipowski
                                           President and Chief Executive Officer


                               POWER OF ATTORNEY

     Each person whose signature appears below hereby constitutes and appoints
Andrew J. Filipowski, Michael P. Cullinane, Larry S. Freedman and Matthew S.
Brown, and each of them, his true and lawful attorneys-in-fact and agents, with
full power of substitution, to sign on his behalf, individually and in each
capacity stated below, all amendments and post-effective amendments to this
Registration Statement on Form S-8 and to file the same, with all exhibits
thereto and any other documents in connection therewith, with the Securities and
Exchange Commission under the Securities Act of 1933, granting unto said
attorneys-in-fact and agents 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 and to all intents and purposes as each might or could do in
person, hereby ratifying and confirming each act that said attorneys-in-fact and
agents may lawfully do or cause to be done by virtue thereof.


                                  SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities indicated on this 19th day of November, 1998.

<TABLE>
<CAPTION>
        Signature                                Title
        ---------                                -----
<S>                        <C>
/s/ ANDREW J. FILIPOWSKI   President, Chief Executive Officer (principal
-------------------------  executive officer) and Chairman of the Board of
    Andrew J. Filipowski   Directors

/s/ MICHAEL P. CULLINANE   Executive Vice President, Chief Financial Officer
-------------------------  (principal financial and accounting officer),
    Michael P. Cullinane   Treasurer and a Director

/s/ PAUL L. HUMENANSKY     Executive Vice President, Chief Operations Officer
-------------------------  and a Director
    Paul L. Humenansky

                           Director
-------------------------
    James E. Cowie

                           Director
-------------------------
    Steven D. Devick

                           Director
-------------------------
    Arthur P. Frigo

/s/ GIAN FULGONI           Director
-------------------------
    Gian Fulgoni
</TABLE>

                                       6
<PAGE>
 
<TABLE>
<CAPTION>
Exhibit                     
Number       Description of Exhibit
------       ----------------------
<C>          <S>
4.5          PLATINUM technology, inc. Restated Broad Based Stock Option Plan.

5            Opinion of counsel as to legality of shares of Common Stock being
             offered (including consent).

15           Acknowledgment of KPMG Peat Marwick LLP Regarding Independent 
             Auditors' Review Report.

23.1         Consent of KPMG Peat Marwick LLP with respect to the Company's
             financial statements.

23.2         Consent of Arthur Andersen LLP with respect to Mastering, Inc.'s
             financial statements.

23.3         Consent of Ernst & Young LLP with respect to Logic Works, Inc.'s
             financial statements.

23.4         Consent of Katten Muchin & Zavis (included in their opinion filed
             as Exhibit 5 herein).

24           Power of Attorney (included on the signature page of this
             Registration Statement).
</TABLE>

                                       7
[{"type": "S-8", "sequence": "1", "description": "FORM S-8", "secsgml_size_bytes": 20913}]
{"company-data": {"conformed-name": "PLATINUM TECHNOLOGY INC", "cik": "0000825703", "assigned-sic": "7372", "irs-number": "363509662", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-67561", "film-number": "98755462"}, "business-address": {"street1": "1815 S MEYERS RD", "city": "OAKBROOK TERRACE", "state": "IL", "zip": "60181", "phone": "6306205000"}, "mail-address": {"street1": "1815 S MEYERS RD", "city": "OAKBROOK TERRACE", "state": "IL", "zip": "60181"}}
As filed with the Securities and Exchange Commission on November 19, 1998
                                                      Registration No. 333-
================================================================================
--------------------------------------------------------------------------------

                      SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C. 20549

                               -----------------

                                   FORM S-8

                            REGISTRATION STATEMENT
                                     Under
                          The Securities Act of 1933

                           PLATINUM technology, inc.
            (Exact name of registrant as specified in its charter)

            Delaware                                         36-3509662
 (State or other jurisdiction of                    (IRS Employer Identification
of incorporation or organization)                             Number)

   1815 South Meyers Road, Oakbrook Terrace, Illinois 60181, (630) 620-5000
          (Address of Principal Executive Offices including Zip Code)

            PLATINUM technology, inc. Broad Based Stock Option Plan
                             (Full title of the plan)

                             Andrew J. Filipowski
   1815 South Meyers Road, Oakbrook Terrace, Illinois 60181, (630) 620-5000
           (Name, address and telephone number of agent for service)

                                  Copies to:
                            Matthew S. Brown, Esq.
                              Mark D. Wood, Esq.
                             Katten Muchin & Zavis
                       525 W. Monroe Street, Suite 1600
                            Chicago, IL 60661-3693
                          Fax Number: (312) 902-1061

                               -----------------
CALCULATION OF REGISTRATION FEE
=========================================================================================================================
                                                                   Proposed maximum   Proposed maximum
                                                                    offering price   aggregate offering     Amount of
Title of securities to be registered   Amount to be registered(1)     per share            price         registration fee
-------------------------------------------------------------------------------------------------------------------------
Common Stock, $.001 par value.......     2,403,300 shares(2)          $20.5416(3)      $ 49,367,627(3)       $13,724.20
-------------------------------------------------------------------------------------------------------------------------
Common Stock, $.001 par value.......    12,596,700 shares(4)          $ 16.625(5)      $209,420,138(5)       $58,218.80
-------------------------------------------------------------------------------------------------------------------------
TOTAL                                   15,000,000 shares                              $258,787,765          $71,943.00
=========================================================================================================================
(1)  Includes an indeterminate number of shares of Common Stock, par value $.001
     per share, of PLATINUM technology, inc. ("PLATINUM Common Stock") that may
     be issuable by reason of stock splits, stock dividends or similar
     transactions. Also includes associated rights (the "Rights") to purchase
     1/100 of a share of Series A Participating Preferred Stock, par value $.01
     per share, of PLATINUM technology, inc. The Rights initially attached to
     and trade with PLATINUM Common Stock. The value attributable to such
     Rights, if any, is reflected in the market price of the PLATINUM Common
     Stock.

(2)  This amount reflects an aggregate of 2,403,300 shares of PLATINUM Common
     Stock issuable upon exercise of outstanding options under the PLATINUM
     technology, inc. Broad Based Stock Option Plan (the "Broad Based Plan")

(3)  Based upon the weighted average exercise price of the shares subject to
     outstanding options under the Broad Based Plan.

(4)  This amount reflects an aggregate of 12,596,700 shares of PLATINUM Common
     Stock which are issuable under the Broad Based Plan.

(5)  Based upon the high and low sales prices of PLATINUM Common Stock, as
     reported on the Nasdaq National Market on November 12, 1998, and used
     solely for the purpose of calculating the registration fee pursuant to Rule
     457 under the Securities Act of 1933.
PART I

                    INFORMATION REQUIRED IN THE PROSPECTUS

     The information called for in Part I of Form S-8 is currently included in
the prospectus for the PLATINUM technology, inc. Broad Based Stock Option Plan
and is not being filed with or included in this Form S-8 in accordance with the
rules and regulations of the Securities and Exchange Commission (the
"Commission").
PART II
              INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

     Item 3. Incorporation of Documents by Reference.

     The following documents have been filed by the Company with the Commission
under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), and
are incorporated in this Registration Statement by reference:

     1.   The Company's Annual Report on Form 10-K for the year ended December
          31, 1997;

     2.   The Company's Quarterly Reports on Form 10-Q for the quarters ended
          March 31, 1998, June 30, 1998 and September 30, 1998;

     3.   The Company's Current Reports on Form 8-K dated January 27, 1998,
          March 3, 1998, April 16, 1998, April 21, 1998 (as amended by a
          Current Report on Form 8-K/A dated May 6, 1998), May 28, 1998, July
          14, 1998, August 4, 1998, August 13, 1998 and October 15, 1998;

     4.   The description of the Common Stock contained in the Company's
          Registration Statement on Form 8-A filed March 7, 1991 pursuant to
          Section 12 of the Exchange Act and all amendments thereto and reports
          filed for the purpose of updating such description; and

     5.   The description of the Rights contained in the Company's Registration
          Statement on Form 8-A filed December 26, 1995 pursuant to Section 12
          of the Exchange Act and all amendments thereto and reports filed for
          the purpose of updating such description.

     In addition, all documents filed by the Company pursuant to Sections 13(a),
13(c), 14 and 15(d) of the Exchange Act, subsequent to the date hereof and prior
to the filing of a post-effective amendment indicating that all securities
offered pursuant to this Registration Statement have been sold or deregistering
all such securities then remaining unsold, shall be deemed to be incorporated by
reference herein and to be part hereof from the date of filing of such
documents. Any statement contained in a document incorporated or deemed to be
incorporated by reference herein shall be deemed to be modified or superseded
for purposes of this Registration Statement to the extent that a statement
contained herein or in any subsequently filed document which also is or is
deemed to be incorporated by reference herein modifies or supersedes such
statement.

Item 4. Description of Securities.

     Not Applicable. 

Item 5. Interests of Named Experts and Counsel.

     Not Applicable.

Item 6. Indemnification of Directors and Officers.

     Article Ten of the Company's Restated Certificate of Incorporation provides
that the Company shall indemnify its directors to the full extent permitted by
the Delaware General Corporation Law and may indemnify its officers to such
extent, except that the Company shall not be obligated to indemnify any such
person (i) with respect to proceedings, claims or actions initiated or brought
voluntarily by any such person and not by way of defense, or (ii) for any
amounts paid in settlement of an action indemnified against by the Company
without the prior written consent of the Company. With the approval of its
stockholders, the Company has entered into indemnity agreements with each of its
directors and certain of its officers. These agreements may require the Company,
among other things, to indemnify such officers and directors against certain
liabilities that may arise by reason of their status or service as directors or
officers, to advance expenses to them as they are incurred, provided that they
undertake to repay the amount advanced if it is ultimately determined by a court
that they are not entitled to indemnification, and to obtain directors' and
officers' liability insurance if available on reasonable terms.

                                       3
In addition, Article Nine of the Company's Restated Certificate of
Incorporation provides that a director of the Company shall not be personally
liable to the Company or its stockholders for monetary damages for breach of his
or her fiduciary duty as a director, except for liability (i) for any breach of
the director's duty of loyalty to the Company 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 General Corporation Law
of the State of Delaware, or (iv) for any transaction from which the director
derives an improper personal benefit.

     Reference is made to Section 145 of the General Corporation Law of the
State of Delaware which provides for indemnification of directors and officers
in certain circumstances.

     The Company has purchased an insurance policy under which it is entitled to
be reimbursed for certain indemnity payments it is required or permitted to make
to its directors and officers.

Item 7. Exemption from Registration Claimed.

     Not Applicable.
Item 8. Exhibits.
4.1     Conformed copy of the Restated Certificate of Incorporation of the
             Company, as amended (incorporated by reference to Exhibit 3.1(d) to
             the Company's Registration Statement on Form S-1, Registration No.
             333-07783).

     4.2     Bylaws of the Company (incorporated by reference to Exhibit 3.2 to
             the Company's Registration Statement on Form S-1, Registration No.
             33-39233 (the "IPO S-1")).

     4.3     Specimen stock certificate representing PLATINUM Common Stock
             (incorporated by reference to Exhibit 4.1 to the IPO S-1).

     4.4     Rights Agreement dated as of December 21, 1995, between the Company
             and Harris Trust and Savings Bank (incorporated by reference to
             Exhibit 1 to the Company's Registration Statement on Form 8-A,
             filed December 26, 1995).

     4.5     PLATINUM technology, inc. Restated Broad Based Stock Option Plan
             (the "Broad Based Plan").

     4.6     Form of Stock Option Agreement under the Broad Based Plan 
             (incorporated by reference to Exhibit 10.4 to the Company's
             Quarterly Report on Form 10-Q for the quarter ended June 30, 1998).

     5       Opinion of counsel as to legality of shares of Common Stock being
             offered (including consent).

     15      Acknowledgment of KPMG Peat Marwick LLP Regarding Independent 
             Auditors' Review Report.

     23.1    Consent of KPMG Peat Marwick LLP with respect to the Company's
             financial statements.

     23.2    Consent of Arthur Andersen LLP with respect to Mastering, Inc.'s
             financial statements.

     23.3    Consent of Ernst & Young LLP with respect to Logic Works, Inc.'s
             financial statements.

     23.4    Consent of Katten Muchin & Zavis (included in their opinion filed
             as Exhibit 5 hereto).

     24      Power of Attorney (included on the signature page of this
             Registration Statement).
Item 9. Undertakings.

     1. The Company hereby undertakes:

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

                                       4
(i) To include any prospectus required by Section 10(a)(3) of the
          Securities Act of 1933;

               (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) 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
          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)(i) and (a)(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 Company pursuant to Section 13 or Section 15(d) of the
     Exchange Act that are incorporated by reference in the Registration
     Statement.

          (b) That, for the purpose of determining any liability under the
     Securities Act of 1933, 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.

          (c) 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.

     2. The Company hereby undertakes that, for the purpose of determining any
liability under the Securities Act of 1933, each filing of the Company's annual
report pursuant to Section 13(a) or 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.

     3. Insofar as indemnification for liabilities arising under the Securities
Act of 1933 may be permitted to directors, officers and controlling persons of
the Company and affiliated companies pursuant to the provisions described in
Item 6 above, or otherwise, the Company has been informed that in the opinion of
the Commission such indemnification is against public policy as expressed in the
Securities Act of 1933 and is therefore unenforceable. In the event that a claim
for indemnification against such liabilities (other than the payment by the
Company of expenses incurred or paid by a director, officer or controlling
person of the Company 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 Company 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 of 1933 and will be governed by the final adjudication of such issue.

                                       5
SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, the Company
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 Oakbrook Terrace, State of Illinois, on this 19th day
of November, 1998.

                                       PLATINUM technology, inc.

                                       By: /s/ ANDREW J. FILIPOWSKI
                                           -------------------------------------
                                           Andrew J. Filipowski
                                           President and Chief Executive Officer

                               POWER OF ATTORNEY

     Each person whose signature appears below hereby constitutes and appoints
Andrew J. Filipowski, Michael P. Cullinane, Larry S. Freedman and Matthew S.
Brown, and each of them, his true and lawful attorneys-in-fact and agents, with
full power of substitution, to sign on his behalf, individually and in each
capacity stated below, all amendments and post-effective amendments to this
Registration Statement on Form S-8 and to file the same, with all exhibits
thereto and any other documents in connection therewith, with the Securities and
Exchange Commission under the Securities Act of 1933, granting unto said
attorneys-in-fact and agents 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 and to all intents and purposes as each might or could do in
person, hereby ratifying and confirming each act that said attorneys-in-fact and
agents may lawfully do or cause to be done by virtue thereof.

                                  SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities indicated on this 19th day of November, 1998.
Signature                                Title
        ---------                                -----
/s/ ANDREW J. FILIPOWSKI   President, Chief Executive Officer (principal
-------------------------  executive officer) and Chairman of the Board of
    Andrew J. Filipowski   Directors

/s/ MICHAEL P. CULLINANE   Executive Vice President, Chief Financial Officer
-------------------------  (principal financial and accounting officer),
    Michael P. Cullinane   Treasurer and a Director

/s/ PAUL L. HUMENANSKY     Executive Vice President, Chief Operations Officer
-------------------------  and a Director
    Paul L. Humenansky

                           Director
-------------------------
    James E. Cowie

                           Director
-------------------------
    Steven D. Devick

                           Director
-------------------------
    Arthur P. Frigo

/s/ GIAN FULGONI           Director
-------------------------
    Gian Fulgoni
6
Exhibit                     
Number       Description of Exhibit
------       ----------------------
4.5          PLATINUM technology, inc. Restated Broad Based Stock Option Plan.

5            Opinion of counsel as to legality of shares of Common Stock being
             offered (including consent).

15           Acknowledgment of KPMG Peat Marwick LLP Regarding Independent 
             Auditors' Review Report.

23.1         Consent of KPMG Peat Marwick LLP with respect to the Company's
             financial statements.

23.2         Consent of Arthur Andersen LLP with respect to Mastering, Inc.'s
             financial statements.

23.3         Consent of Ernst & Young LLP with respect to Logic Works, Inc.'s
             financial statements.

23.4         Consent of Katten Muchin & Zavis (included in their opinion filed
             as Exhibit 5 herein).

24           Power of Attorney (included on the signature page of this
             Registration Statement).
7