<PAGE>   1
          As filed with the Securities and Exchange Commission on April 26, 1996
                                              Registration No. 33-
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

 
                                    FORM S-8

                             REGISTRATION STATEMENT
                                     Under
                           THE SECURITIES ACT OF 1933


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


       California                                        94-2748530
(State of Incorporation)                    (I.R.S. Employer Identification No.)


                          691 South Milpitas Boulevard
                           Milpitas, California 95035
                    (Address of principal executive offices)


                                1990 STOCK PLAN
                            (Full title of the Plan)


                                F. GRANT SAVIERS
                      President and Chief Executive Officer
                                  ADAPTEC, INC.
                          691 South Milpitas Boulevard
                           Milpitas, California 95035
                                 (408) 945-8600
            (Name, address and telephone number of agent for service)


                                   Copies to:

                           HENRY P. MASSEY, JR., ESQ.
                       Wilson, Sonsini, Goodrich & Rosati
                            Professional Corporation
                               650 Page Mill Road
                        Palo Alto, California 94304-1050
                                 (415) 493-9300


================================================================================
<PAGE>   2
<TABLE>
<CAPTION>
==============================================================================================
                         CALCULATION OF REGISTRATION FEE
==============================================================================================
                                                      Proposed      Proposed
                Title of                              Maximum        Maximum
               Securities               Amount        Offering      Aggregate       Amount of
                  to be                 to be          Price        Offering      Registration
               Registered             Registered     Per Share        Price            Fee
- ----------------------------------------------------------------------------------------------
<S>                                  <C>             <C>          <C>             <C>    
Common Stock                         2,253,340(1)    $51.625(2)   $116,328,678       $40,114
  $.001 par value, to be issued
  under 1990 Stock Plan
==============================================================================================
</TABLE>

(1)    For the sole purpose of calculating the registration fee, the number of
       shares to be registered under this Registration Statement is the number
       of additional shares authorized to be issued under the 1990 Stock Plan.

(2)    Estimated in accordance with Rule 457(h) under the Securities Act of
       1933, as amended (the "Securities Act") solely for the purpose of
       calculating the total registration fee. Computation based upon the
       average of the high and low prices of the Common Stock as reported on the
       Nasdaq National Market on April 19, 1996 because the price at which the
       options to be granted in the future may be exercised is not currently
       determinable.
<PAGE>   3
           PART II: INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.  Information Incorporated by Reference

         The following documents and information heretofore filed with the
Securities and Exchange Commission are hereby incorporated by reference:

         (a)      The Registrant's Annual Report on Form 10-K, file no. 0-15071
                  filed on June 28, 1995, which contains audited financial
                  statements for the Registrant's fiscal year ended March 31,
                  1995.

         (b)      1.  The Registrant's Quarterly Report on Form 10-Q, file no. 
                  0-15071, filed on August 10, 1995, which contains the
                  Registrant's unaudited financial statements as of June 30,
                  1995.

                  2.  The Registrant's Quarterly Report on Form 10-Q, file no.
                  0-15071, filed on November 13, 1995, which contains the
                  Registrant's unaudited financial statements as of September
                  29, 1995.

                  3.  The Registrant's Quarterly Report on 10-Q, file no. 
                  0-15071, filed on February 9, 1996, which contains the
                  Registrant's unaudited financial statements as of December 29,
                  1995.

         (c)      Items 1 and 2 of the Registrant's Registration Statement
                  Amendment on Form 8-A filed on July 20, 1992 pursuant to
                  Section 12 of the Securities Exchange Act of 1934, as amended
                  (the "Exchange Act").

         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 which 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 part
hereof from the date of filing 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

         Section 317 of the California General Corporation law makes provisions
for the indemnification of officers, directors, and other corporate agents in
terms sufficiently broad to indemnify such persons, under certain circum
stances, for liabilities (including reimbursement of expenses incurred) arising
under the Securities Act. The Registrant has entered into indemnification
agreements to such effect with its officers and directors.


                                      II-1
<PAGE>   4
         Article IV of Registrant's Articles of Incorporation and Article VI of
the Bylaws of Registrant provide that the Registrant shall indemnify certain
agents of the Registrant to the maximum extent permitted by the California
Corporations Code. Persons covered by this indemnification provision include
current and former directors, officers, employees and other agents of the
Registrant as well as persons who serve at the request of the Registrant as
directors, officers, employees or agents of another enterprise.

         The Registrant shall have the power, to the extent and in the manner
permitted by Section 317 of the California Corporations Code, to indemnify each
of its employees and agents (other than directors and officers) against
expenses, judgments, fines, settlements, and other amounts actually and
reasonably incurred in connection with any proceeding arising by reason of the
fact that such person is or was an agent of the Company. For this purpose, an
"employee" or "agent" of the Registrant includes any person (i) who is or was an
employee or agent of Registrant, (ii) who is or was serving at the request of
Registrant as an employee or agent of another corporation, partnership, joint
venture, trust or other enterprise, or (iii) who was an employee or agent of a
corporation which was a predecessor corporation of Registrant or of another
enterprise at the request of such predecessor corporation.

         The Registrant has entered into separate indemnification agreements
with its directors and officers, which may require the Registrant, among other
things, to indemnify them against certain liabilities that may arise by reason
of their status or service as directors or officers (other than liabilities
arising from willful misconduct of a culpable nature), and to advance their
expenses incurred as a result of any proceeding against them as to which they
could be indemnified.

ITEM 7.  Exemption From Registration Claimed

         Not Applicable.

ITEM 8.  Exhibits

              4.1     First Amended and Restated Common Shares Rights Agreement
                      between Registrant and Chemical Trust Company as Rights
                      Agents, dated June 30, 1992. (Incorporated by reference to
                      Exhibit 1.1 to Amendment No. 3 on Form 8 (filed July 20,
                      1992) to the Registrant's Registration Statement (No.
                      0-15071) on Form 8-A filed on May 11, 1992.)

              4.2     1990 Stock Plan, as amended.  (Incorporated by reference 
                      to Exhibit 4.2 filed with Registrant's Registration
                      Statement on Form S-8 filed on February 7, 1996 (file no.
                      333-00779)).

              4.3     Forms of Stock Option Agreement and Incentive Stock Rights
                      Agreement for use in connection with the 1990 Stock Plan,
                      as amended. (Incorporated by reference to Exhibit 4.3
                      filed with Registrant's Registration Statement on Form S-8
                      filed on February 7, 1996 (file no. 333-00779)).

              4.4     Forms of Tandem Stock Option/SAR Agreement, Restricted
                      Stock Purchase Agreement and Stock Appreciation Rights
                      Agreement for use in connection with the 1990 Stock Plan,
                      as amended. (Incorporated by reference to Exhibit 10.24
                      filed with Registrant's Annual Report on Form 10-K for the
                      year ended March 31, 1993)

              5.1     Opinion of Wilson, Sonsini, Goodrich & Rosati, P.C., as to
                      legality of securities being registered.

             23.1     Consent of Independent Accountants (see Page II-6).


                                      II-2
<PAGE>   5
             23.2     Consent of Counsel (contained in Exhibit 5.1).

             24.1     Power of Attorney (see Page II-4).

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 to include
any material information with respect to the plan of distribution not previously
disclosed in this Registration Statement or any material change to such
information in this Registration Statement.

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

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

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

         (C)     Insofar as indemnification for liabilities arising under the
Securities Act may be permitted to directors, officers and controlling persons
of the Registrant pursuant to the California General Corporations Code, the
Restated Articles of Incorporation of the Registrant, the Bylaws of the
Registrant, Indemnification Agreements entered into between the Registrant and
its officers and directors, 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.


                                      II-3
<PAGE>   6
                                   SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, the
Registrant, Adaptec, Inc, a corporation organized and existing under the laws of
the State of California, 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 Milpitas, State of California, on this
17th day of April, 1996.


                                        ADAPTEC, INC.

                                        By:  /s/ F. Grant Saviers
                                             ----------------------------------
                                             F. Grant Saviers
                                             Chief Executive Officer, President
                                             and Director



                                POWER OF ATTORNEY

         KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature
appears below constitutes and appoints F. Grant Saviers and Paul G. Hansen,
jointly and severally, his attorneys-in-fact, each with the power of
substitution, for him in any and all capacities, to sign any amendments to this
Registration Statement on Form S-8, and to file the same, with exhibits thereto
and other documents in connection therewith, with the Securities and Exchange
Commission, hereby ratifying and confirming all that each of said
attorneys-in-fact, or his substitute or substitutes, may do or cause to be done
by virtue hereof.

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



<TABLE>
<CAPTION>
          SIGNATURE                             TITLE                               DATE
          ---------                             -----                               ----
<S>                              <C>                                          <C>


/s/ F. Grant Saviers             Chief Executive Officer, President and       April 17, 1996
- -----------------------------    Director (Principal Executive Officer)
        (F. Grant Saviers)     


/s/ Paul G. Hansen               Vice President of Finance, Chief             April 19, 1996
- -----------------------------    Financial Officer (Principal Financial
        (Paul G. Hansen)         Officer) and Assistant Secretary
</TABLE>
                                            

                                      II-4
<PAGE>   7
<TABLE>
<S>                               <C>                                         <C> 
/s/ Andrew J. Brown               Corporate Controller (Principal             April 17, 1996
- ------------------------------    Accounting Officer)
        (Andrew J. Brown)         
                                  
                                  
/s/ John G. Adler                 Chairman of the Board and Director          April 25, 1996
- ------------------------------    
        (John G. Adler)           
                                  
                                  
/s/ Laurence B. Bourcher          Director                                    April 18, 1996
- ------------------------------    
     (Laurence B. Boucher)        
                                  
                                  
/s/ Carl J. Conti                 Director                                    April 25, 1996
- ------------------------------    
        (Carl J. Conti)           
                                  
                                  
/s/ John East                     Director                                    April 19, 1996
          (John East)             
                                  
/s/ Robert J. Loarie              Director                                    April 22, 1996
- ------------------------------    
      (Robert J. Loarie)          
                                  
                                  
/s/ B.J. Moore                    Director                                    April 18, 1996
- ------------------------------    
        (B.J. Moore)              
                                  
                                  
/s/ W. Ferrell Sanders            Director                                    April 19, 1996
- ------------------------------    
    (W. Ferrell Sanders)          
                                  
                                  
/s/ Phillip E. White              Director                                    April 22, 1996
- ------------------------------    
    (Phillip E. White)            
</TABLE>
                                  
                                  
                                
                                      II-5
<PAGE>   8
                       CONSENT OF INDEPENDENT ACCOUNTANTS

         We hereby consent to the incorporation by reference in this
Registration Statement on Form S-8 of our report dated April 20, 1995, which
appears on page 47 of the 1995 Annual Report to Shareholders of Adaptec, Inc.,
which is incorporated by reference in Adaptec, Inc.'s Annual Report on Form 10-K
for the year ended March 31, 1995.



/s/ PRICE WATERHOUSE LLP


San Jose, California
April 22, 1996








                                      II-6
<PAGE>   9
                    CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS

As independent public accountants, we hereby consent to the incorporation by
reference in this Registration Statement of our report dated April 25, 1994
included in Adaptec, Inc.'s Form 10-K for the year ended March 31, 1995.




                                       /s/ ARTHUR ANDERSEN LLP




San Jose, California
April 18, 1996









                                      II-7
<PAGE>   10
                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549




                                    EXHIBITS




                       Registration Statement on Form S-8

                                  ADAPTEC, INC.

                                 April 26, 1996
<PAGE>   11
                                INDEX TO EXHIBITS

   Exhibit                                                                 Page
   Number                                                                   No.
- ------------                                                              ------
     4.1(1)      First Amended and Restated Common Shares Rights 
                 Agreement between Registrant and Chemical Trust
                 Company as Rights Agents, dated June 30, 1992.
                 
     4.2(2)      1990 Stock Plan, as amended.
                 
     4.3(3)      Forms of Stock Option Agreement and Incentive Stock 
                 Rights Agreement for use in connection with the
                 1990 Stock Plan, as amended.
                 
     4.4(4)      Forms of Tandem Stock Option/SAR Agreement, Restricted 
                 Stock Purchase Agreement and Stock Appreciation
                 Rights Agreement for use in connection with the
                 1990 Stock Plan, as amended.
                 
     5.1         Opinion of counsel as to legality of securities being 
                 registered.

    23.1         Consent of Independent Accountants (see page II-6).

    23.2         Consent of Counsel (contained in Exhibit 5.1).
                 
    24.1         Power of Attorney (see page II-4).
                 
================================================================================

(1)      Incorporated by reference to Exhibit 1.1 to Amendment No. 3 on Form 8 
         (filed July 20, 1992) to the Registrant's Registration Statement (No.
         0-15071) on Form 8-A filed on May 11, 1992.

(2)      Incorporated by reference to Exhibit 4.2 filed with Registrant's 
         Registration Statement on form S-8 filed on February 7, 1996 (file no.
         333-00779).

(3)      Incorporated by reference to Exhibit 4.3 filed with Registrant's 
         Registration Statement on form S-8 filed on February 7, 1996 (file no.
         333-00779).

(4)      Incorporated by reference to Exhibit 10.24 filed with Registrant's
         Annual Report on Form 10-K for the year ended March 31, 1993 filed June
         28, 1993.
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1
          As filed with the Securities and Exchange Commission on April 26, 1996
                                              Registration No. 33-
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

 
                                    FORM S-8

                             REGISTRATION STATEMENT
                                     Under
                           THE SECURITIES ACT OF 1933

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

       California                                        94-2748530
(State of Incorporation)                    (I.R.S. Employer Identification No.)

                          691 South Milpitas Boulevard
                           Milpitas, California 95035
                    (Address of principal executive offices)

                                1990 STOCK PLAN
                            (Full title of the Plan)

                                F. GRANT SAVIERS
                      President and Chief Executive Officer
                                  ADAPTEC, INC.
                          691 South Milpitas Boulevard
                           Milpitas, California 95035
                                 (408) 945-8600
            (Name, address and telephone number of agent for service)

                                   Copies to:

                           HENRY P. MASSEY, JR., ESQ.
                       Wilson, Sonsini, Goodrich & Rosati
                            Professional Corporation
                               650 Page Mill Road
                        Palo Alto, California 94304-1050
                                 (415) 493-9300

================================================================================
2
==============================================================================================
                         CALCULATION OF REGISTRATION FEE
==============================================================================================
                                                      Proposed      Proposed
                Title of                              Maximum        Maximum
               Securities               Amount        Offering      Aggregate       Amount of
                  to be                 to be          Price        Offering      Registration
               Registered             Registered     Per Share        Price            Fee
- ----------------------------------------------------------------------------------------------
Common Stock                         2,253,340(1)    $51.625(2)   $116,328,678       $40,114
  $.001 par value, to be issued
  under 1990 Stock Plan
==============================================================================================
(1)    For the sole purpose of calculating the registration fee, the number of
       shares to be registered under this Registration Statement is the number
       of additional shares authorized to be issued under the 1990 Stock Plan.

(2)    Estimated in accordance with Rule 457(h) under the Securities Act of
       1933, as amended (the "Securities Act") solely for the purpose of
       calculating the total registration fee. Computation based upon the
       average of the high and low prices of the Common Stock as reported on the
       Nasdaq National Market on April 19, 1996 because the price at which the
       options to be granted in the future may be exercised is not currently
       determinable.
3
           PART II: INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.  Information Incorporated by Reference

         The following documents and information heretofore filed with the
Securities and Exchange Commission are hereby incorporated by reference:

         (a)      The Registrant's Annual Report on Form 10-K, file no. 0-15071
                  filed on June 28, 1995, which contains audited financial
                  statements for the Registrant's fiscal year ended March 31,
                  1995.

         (b)      1.  The Registrant's Quarterly Report on Form 10-Q, file no. 
                  0-15071, filed on August 10, 1995, which contains the
                  Registrant's unaudited financial statements as of June 30,
                  1995.

                  2.  The Registrant's Quarterly Report on Form 10-Q, file no.
                  0-15071, filed on November 13, 1995, which contains the
                  Registrant's unaudited financial statements as of September
                  29, 1995.

                  3.  The Registrant's Quarterly Report on 10-Q, file no. 
                  0-15071, filed on February 9, 1996, which contains the
                  Registrant's unaudited financial statements as of December 29,
                  1995.

         (c)      Items 1 and 2 of the Registrant's Registration Statement
                  Amendment on Form 8-A filed on July 20, 1992 pursuant to
                  Section 12 of the Securities Exchange Act of 1934, as amended
                  (the "Exchange Act").

         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 which 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 part
hereof from the date of filing 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

         Section 317 of the California General Corporation law makes provisions
for the indemnification of officers, directors, and other corporate agents in
terms sufficiently broad to indemnify such persons, under certain circum
stances, for liabilities (including reimbursement of expenses incurred) arising
under the Securities Act. The Registrant has entered into indemnification
agreements to such effect with its officers and directors.

                                      II-1
4
         Article IV of Registrant's Articles of Incorporation and Article VI of
the Bylaws of Registrant provide that the Registrant shall indemnify certain
agents of the Registrant to the maximum extent permitted by the California
Corporations Code. Persons covered by this indemnification provision include
current and former directors, officers, employees and other agents of the
Registrant as well as persons who serve at the request of the Registrant as
directors, officers, employees or agents of another enterprise.

         The Registrant shall have the power, to the extent and in the manner
permitted by Section 317 of the California Corporations Code, to indemnify each
of its employees and agents (other than directors and officers) against
expenses, judgments, fines, settlements, and other amounts actually and
reasonably incurred in connection with any proceeding arising by reason of the
fact that such person is or was an agent of the Company. For this purpose, an
"employee" or "agent" of the Registrant includes any person (i) who is or was an
employee or agent of Registrant, (ii) who is or was serving at the request of
Registrant as an employee or agent of another corporation, partnership, joint
venture, trust or other enterprise, or (iii) who was an employee or agent of a
corporation which was a predecessor corporation of Registrant or of another
enterprise at the request of such predecessor corporation.

         The Registrant has entered into separate indemnification agreements
with its directors and officers, which may require the Registrant, among other
things, to indemnify them against certain liabilities that may arise by reason
of their status or service as directors or officers (other than liabilities
arising from willful misconduct of a culpable nature), and to advance their
expenses incurred as a result of any proceeding against them as to which they
could be indemnified.

ITEM 7.  Exemption From Registration Claimed

         Not Applicable.

ITEM 8.  Exhibits

              4.1     First Amended and Restated Common Shares Rights Agreement
                      between Registrant and Chemical Trust Company as Rights
                      Agents, dated June 30, 1992. (Incorporated by reference to
                      Exhibit 1.1 to Amendment No. 3 on Form 8 (filed July 20,
                      1992) to the Registrant's Registration Statement (No.
                      0-15071) on Form 8-A filed on May 11, 1992.)

              4.2     1990 Stock Plan, as amended.  (Incorporated by reference 
                      to Exhibit 4.2 filed with Registrant's Registration
                      Statement on Form S-8 filed on February 7, 1996 (file no.
                      333-00779)).

              4.3     Forms of Stock Option Agreement and Incentive Stock Rights
                      Agreement for use in connection with the 1990 Stock Plan,
                      as amended. (Incorporated by reference to Exhibit 4.3
                      filed with Registrant's Registration Statement on Form S-8
                      filed on February 7, 1996 (file no. 333-00779)).

              4.4     Forms of Tandem Stock Option/SAR Agreement, Restricted
                      Stock Purchase Agreement and Stock Appreciation Rights
                      Agreement for use in connection with the 1990 Stock Plan,
                      as amended. (Incorporated by reference to Exhibit 10.24
                      filed with Registrant's Annual Report on Form 10-K for the
                      year ended March 31, 1993)

              5.1     Opinion of Wilson, Sonsini, Goodrich & Rosati, P.C., as to
                      legality of securities being registered.

             23.1     Consent of Independent Accountants (see Page II-6).

                                      II-2
5
             23.2     Consent of Counsel (contained in Exhibit 5.1).

             24.1     Power of Attorney (see Page II-4).

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 to include
any material information with respect to the plan of distribution not previously
disclosed in this Registration Statement or any material change to such
information in this Registration Statement.

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

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

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

         (C)     Insofar as indemnification for liabilities arising under the
Securities Act may be permitted to directors, officers and controlling persons
of the Registrant pursuant to the California General Corporations Code, the
Restated Articles of Incorporation of the Registrant, the Bylaws of the
Registrant, Indemnification Agreements entered into between the Registrant and
its officers and directors, 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.

                                      II-3
6
                                   SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, the
Registrant, Adaptec, Inc, a corporation organized and existing under the laws of
the State of California, 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 Milpitas, State of California, on this
17th day of April, 1996.

                                        ADAPTEC, INC.

                                        By:  /s/ F. Grant Saviers
                                             ----------------------------------
                                             F. Grant Saviers
                                             Chief Executive Officer, President
                                             and Director

                                POWER OF ATTORNEY

         KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature
appears below constitutes and appoints F. Grant Saviers and Paul G. Hansen,
jointly and severally, his attorneys-in-fact, each with the power of
substitution, for him in any and all capacities, to sign any amendments to this
Registration Statement on Form S-8, and to file the same, with exhibits thereto
and other documents in connection therewith, with the Securities and Exchange
Commission, hereby ratifying and confirming all that each of said
attorneys-in-fact, or his substitute or substitutes, may do or cause to be done
by virtue hereof.

         Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities and on the dates indicated.
SIGNATURE                             TITLE                               DATE
          ---------                             -----                               ----
/s/ F. Grant Saviers             Chief Executive Officer, President and       April 17, 1996
- -----------------------------    Director (Principal Executive Officer)
        (F. Grant Saviers)     

/s/ Paul G. Hansen               Vice President of Finance, Chief             April 19, 1996
- -----------------------------    Financial Officer (Principal Financial
        (Paul G. Hansen)         Officer) and Assistant Secretary
II-4
7
/s/ Andrew J. Brown               Corporate Controller (Principal             April 17, 1996
- ------------------------------    Accounting Officer)
        (Andrew J. Brown)         
                                  
                                  
/s/ John G. Adler                 Chairman of the Board and Director          April 25, 1996
- ------------------------------    
        (John G. Adler)           
                                  
                                  
/s/ Laurence B. Bourcher          Director                                    April 18, 1996
- ------------------------------    
     (Laurence B. Boucher)        
                                  
                                  
/s/ Carl J. Conti                 Director                                    April 25, 1996
- ------------------------------    
        (Carl J. Conti)           
                                  
                                  
/s/ John East                     Director                                    April 19, 1996
          (John East)             
                                  
/s/ Robert J. Loarie              Director                                    April 22, 1996
- ------------------------------    
      (Robert J. Loarie)          
                                  
                                  
/s/ B.J. Moore                    Director                                    April 18, 1996
- ------------------------------    
        (B.J. Moore)              
                                  
                                  
/s/ W. Ferrell Sanders            Director                                    April 19, 1996
- ------------------------------    
    (W. Ferrell Sanders)          
                                  
                                  
/s/ Phillip E. White              Director                                    April 22, 1996
- ------------------------------    
    (Phillip E. White)
II-5
8
                       CONSENT OF INDEPENDENT ACCOUNTANTS

         We hereby consent to the incorporation by reference in this
Registration Statement on Form S-8 of our report dated April 20, 1995, which
appears on page 47 of the 1995 Annual Report to Shareholders of Adaptec, Inc.,
which is incorporated by reference in Adaptec, Inc.'s Annual Report on Form 10-K
for the year ended March 31, 1995.

/s/ PRICE WATERHOUSE LLP

San Jose, California
April 22, 1996

                                      II-6
9
                    CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS

As independent public accountants, we hereby consent to the incorporation by
reference in this Registration Statement of our report dated April 25, 1994
included in Adaptec, Inc.'s Form 10-K for the year ended March 31, 1995.

                                       /s/ ARTHUR ANDERSEN LLP

San Jose, California
April 18, 1996

                                      II-7
10
                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549

                                    EXHIBITS

                       Registration Statement on Form S-8

                                  ADAPTEC, INC.

                                 April 26, 1996
11
                                INDEX TO EXHIBITS

   Exhibit                                                                 Page
   Number                                                                   No.
- ------------                                                              ------
     4.1(1)      First Amended and Restated Common Shares Rights 
                 Agreement between Registrant and Chemical Trust
                 Company as Rights Agents, dated June 30, 1992.
                 
     4.2(2)      1990 Stock Plan, as amended.
                 
     4.3(3)      Forms of Stock Option Agreement and Incentive Stock 
                 Rights Agreement for use in connection with the
                 1990 Stock Plan, as amended.
                 
     4.4(4)      Forms of Tandem Stock Option/SAR Agreement, Restricted 
                 Stock Purchase Agreement and Stock Appreciation
                 Rights Agreement for use in connection with the
                 1990 Stock Plan, as amended.
                 
     5.1         Opinion of counsel as to legality of securities being 
                 registered.

    23.1         Consent of Independent Accountants (see page II-6).

    23.2         Consent of Counsel (contained in Exhibit 5.1).
                 
    24.1         Power of Attorney (see page II-4).
                 
================================================================================

(1)      Incorporated by reference to Exhibit 1.1 to Amendment No. 3 on Form 8 
         (filed July 20, 1992) to the Registrant's Registration Statement (No.
         0-15071) on Form 8-A filed on May 11, 1992.

(2)      Incorporated by reference to Exhibit 4.2 filed with Registrant's 
         Registration Statement on form S-8 filed on February 7, 1996 (file no.
         333-00779).

(3)      Incorporated by reference to Exhibit 4.3 filed with Registrant's 
         Registration Statement on form S-8 filed on February 7, 1996 (file no.
         333-00779).

(4)      Incorporated by reference to Exhibit 10.24 filed with Registrant's
         Annual Report on Form 10-K for the year ended March 31, 1993 filed June
         28, 1993.