<PAGE>
 
             As filed with the Securities and Exchange Commission
                               on July 23, 1997
                                                   Registration No. 333-
                                                                        ------
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

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

                                    FORM S-8

                             REGISTRATION STATEMENT
                                     Under
                           THE SECURITIES ACT OF 1933

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

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


        Delaware                                             06-1236189
---------------------------------              -----------------------------
(State or other jurisdiction of             (I.R.S. Employer Identification No.)
 incorporation or organization)
                               

                     8 Progress Drive, Shelton, CT  06484
           ---------------------------------------------------------
              (Address of principal executive offices) (Zip Code)

                  SECOND AMENDED AND RESTATED 1995 STOCK PLAN
                  -------------------------------------------
                            (Full title of the plan)

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

                                DR. SANTANU DAS
                     President and Chief Executive Officer
                             TRANSWITCH CORPORATION
                                8 Progress Drive
                          Shelton, Connecticut  06484
                                 (203) 929-8810
            (Name, address including zip code and telephone number,
                   including area code, of agent for service)

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

                                    Copy to:

                                STEVEN C. BROWNE
                        Testa, Hurwitz & Thibeault, LLP
                               High Street Tower
                                125 High Street
                               Boston, MA  02110
                                 (617) 248-7000

================================================================================
<PAGE>
 
                        CALCULATION OF REGISTRATION FEE
<TABLE>
<CAPTION>
 
================================================================================== 
                       
                                         Proposed       Proposed
      Title of                           Maximum        Maximum
     Securities            Amount        Offering      Aggregate      Amount of
       to be               to be        Price Per       Offering     Registration
     Registered          Registered       Share          Price           Fee
----------------------------------------------------------------------------------
                       
<S>                    <C>             <C>           <C>             <C>
Second Amended      
and Restated 1995   
Stock Plan          
Common Stock,       
$.001 par value        900,000 shares     $8.75(1)    $7,875,000(1)  $2,387.00
 
================================================================================== 
 
</TABLE>
(1)  The price of  $8.75 per share, which is the average of the high and low
     prices reported on the Nasdaq National Market on July 17, 1997, is set
     forth solely for purposes of calculating the filing fee pursuant to Rule
     457(c).
================================================================================

                                       2
<PAGE>
 
     This Registration Statement registers additional securities of the same
class as other securities for which a registration statement filed on this form
relating to the Registrant's 1989 Stock Option Plan, 1995 Stock Plan, 1995 Non-
Employee Director Stock Option Plan and 1995 Employee Stock Purchase Plan is
effective.  Pursuant to General Instruction E to Form S-8, the Registrant hereby
incorporates by reference herein the information contained in the Registrant's
Registration Statement on Form S-8 (Registration No. 33-94234) as filed with the
Securities and Exchange Commission (the "Commission") on June 30, 1995.

                                    PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3.  Incorporation of Documents by Reference.
         --------------------------------------- 

     The following documents filed with the Commission are incorporated by
reference in this Registration Statement:

     (a)  Registrant's Annual Report on Form 10-K (Commission File Number 
          0-25996) for the fiscal year ended December 31, 1996, filed with the
          Commission on March 28, 1997; and

     (b)  Registrant's Quarterly Report on Form 10-Q (Commission File Number 
          0-25996) for the fiscal quarter ended March 31, 1997, filed with the
          Commission on May 12, 1997.

     All documents subsequently filed with the Commission 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 herein 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 8.  Exhibits
         --------

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

     Exhibit 4.1  Specimen certificate representing the Common Stock of the
                  Registrant (filed as Exhibit 4.1 to Registrant's Registration
                  Statement on Form S-1 (File No. 33-91694) and incorporated
                  herein by reference).

     Exhibit 4.2  Amended and Restated Certificate of Incorporation of the
                  Registrant (filed as Exhibit 3.2 to Registrant's Registration
                  Statement on Form S-1 (File No. 33-91694) and incorporated
                  herein by reference).

                                       3
<PAGE>
 
     Exhibit 4.3   By-laws of the Registrant, as amended and restated (filed as
                   Exhibit 3.3 to Registrant's Registration Statement on Form 
                   S-1 (File No. 33-91694) and incorporated herein by
                   reference).

     Exhibit 4.4   Second Amended and Restated 1995 Stock Plan (filed as Exhibit
                   10.2 to Registrant's Annual Report on Form 10-K for the
                   fiscal year ended December 31, 1996 and incorporated herein
                   by reference).

     Exhibit 4.5   Form of Incentive Stock Option Agreement under the Second
                   Amended and Restated 1995 Stock Plan of the Registrant.

     Exhibit 4.6   Form of Non-Qualified Stock Option Agreement under the Second
                   Amended and Restated 1995 Stock Plan of the Registrant.

     Exhibit 5.1   Opinion of Testa, Hurwitz & Thibeault, LLP.

     Exhibit 23.1  Consent of KPMG Peat Marwick LLP.

     Exhibit 23.2  Consent of Testa, Hurwitz & Thibeault, LLP (included in
                   Exhibit 5.1).

     Exhibit 24.1  Power of Attorney (included as part of the signature page to
                   this Registration Statement).

                                       4
<PAGE>
 
                                   SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, the Registrant,
TranSwitch Corporation, 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 Shelton, State of Connecticut, on this July 10,
1997.

                                    TRANSWITCH CORPORATION



                                    By: /s/ Dr. Santanu Das
                                        -------------------
                                        Dr. Santanu Das
                                        President, Chief Executive Officer



                               POWER OF ATTORNEY

     KNOW ALL PERSONS BY THESE PRESENTS, that each such person whose signature
appears below constitutes and appoints, jointly and severally, Dr. Santanu Das
and Michael F. Stauff 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 (including post-effective amendments), and to
file the same, with all 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.
<PAGE>
 
          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/ Dr. Santanu Das          President, Chief Executive            July 10, 1997
---------------------------  Officer and Director        
Dr. Santanu Das              (Principal Executive Officer)
                                                          
 
/s/ Michael F. Stauff        Vice President, Chief Financial       July 10, 1997
---------------------------  Officer and Treasurer
Michael F. Stauff            (Principal Financial and Accounting
                             Officer)                            
                                                                 
/s/ Dr. Steward S. Flaschen  Director                              July 10, 1997
---------------------------  
Dr. Steward S. Flaschen
 
/s/ Dr. Charles Lee          Director                              July 10, 1997
---------------------------
Dr. Charles Lee
 
/s/ Dr. Ljubomir Micic       Director                              July 10, 1997
---------------------------
Dr. Ljubomir Micic
 
/s/ Dr. Albert E. Paladino   Director                              July 10, 1997
---------------------------  
Dr. Albert E. Paladino
 
</TABLE>
<PAGE>
 
                               INDEX TO EXHIBITS
<TABLE>
<CAPTION>
 
 
 
Exhibit                      Description of Exhibit
-------                      ----------------------
<S>            <C>
Exhibit 4.1    Specimen certificate representing the Common Stock of the
               Registrant (filed as Exhibit 4.1 to Registrant's Registration
               Statement on Form S-1 (File No. 33-91694) and incorporated herein
               by reference).

Exhibit 4.2    Amended and Restated Certificate of Incorporation of the
               Registrant (filed as Exhibit 3.2 to Registrant's Registration
               Statement on Form S-1 (File No. 33-91694) and incorporated herein
               by reference).

Exhibit 4.3    By-laws of the Registrant, as amended and restated (filed as
               Exhibit 3.3 to Registrant's Registration Statement on Form S-1
               (File No. 33-91694) and incorporated herein by reference).

Exhibit 4.4    Second Amended and Restated 1995 Stock Plan (filed as Exhibit
               10.2 to Registrant's Annual Report on Form 10-K and incorporated
               herein by reference).

Exhibit 4.5    Form of Incentive Stock Option Agreement under the Second Amended
               and Restated 1995 Stock Plan of the Registrant.

Exhibit 4.6    Form of Non-Qualified Stock Option Agreement under the Second
               Amended and Restated 1995 Stock Plan of the Registrant.

Exhibit 5.1    Opinion of Testa, Hurwitz & Thibeault, LLP.

Exhibit 23.1   Consent of KPMG Peat Marwick LLP.

Exhibit 23.2   Consent of Testa, Hurwitz & Thibeault, LLP (included in 
               Exhibit 5.1).

Exhibit 24.1   Power of Attorney (included as part of the signature page to this
               Registration Statement).
</TABLE>
[{"type": "S-8", "sequence": "1", "description": "FORM S-8", "secsgml_size_bytes": 12561}]
{"company-data": {"conformed-name": "TRANSWITCH CORP /DE", "cik": "0000944739", "assigned-sic": "3674", "irs-number": "061236189", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-31849", "film-number": "97644069"}, "business-address": {"street1": "8 PROGRESS DR", "city": "SHELTON", "state": "CT", "zip": "06484", "phone": "2039298810"}, "mail-address": {"street1": "8 PROGRESS DR", "city": "SHELTON", "state": "CT", "zip": "06484"}}
As filed with the Securities and Exchange Commission
                               on July 23, 1997
                                                   Registration No. 333-
                                                                        ------
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

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

                                    FORM S-8

                             REGISTRATION STATEMENT
                                     Under
                           THE SECURITIES ACT OF 1933

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

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

        Delaware                                             06-1236189
---------------------------------              -----------------------------
(State or other jurisdiction of             (I.R.S. Employer Identification No.)
 incorporation or organization)
                               

                     8 Progress Drive, Shelton, CT  06484
           ---------------------------------------------------------
              (Address of principal executive offices) (Zip Code)

                  SECOND AMENDED AND RESTATED 1995 STOCK PLAN
                  -------------------------------------------
                            (Full title of the plan)

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

                                DR. SANTANU DAS
                     President and Chief Executive Officer
                             TRANSWITCH CORPORATION
                                8 Progress Drive
                          Shelton, Connecticut  06484
                                 (203) 929-8810
            (Name, address including zip code and telephone number,
                   including area code, of agent for service)

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

                                    Copy to:

                                STEVEN C. BROWNE
                        Testa, Hurwitz & Thibeault, LLP
                               High Street Tower
                                125 High Street
                               Boston, MA  02110
                                 (617) 248-7000

================================================================================
CALCULATION OF REGISTRATION FEE
================================================================================== 
                       
                                         Proposed       Proposed
      Title of                           Maximum        Maximum
     Securities            Amount        Offering      Aggregate      Amount of
       to be               to be        Price Per       Offering     Registration
     Registered          Registered       Share          Price           Fee
----------------------------------------------------------------------------------
Second Amended      
and Restated 1995   
Stock Plan          
Common Stock,       
$.001 par value        900,000 shares     $8.75(1)    $7,875,000(1)  $2,387.00
 
==================================================================================
(1)  The price of  $8.75 per share, which is the average of the high and low
     prices reported on the Nasdaq National Market on July 17, 1997, is set
     forth solely for purposes of calculating the filing fee pursuant to Rule
     457(c).
================================================================================

                                       2
This Registration Statement registers additional securities of the same
class as other securities for which a registration statement filed on this form
relating to the Registrant's 1989 Stock Option Plan, 1995 Stock Plan, 1995 Non-
Employee Director Stock Option Plan and 1995 Employee Stock Purchase Plan is
effective.  Pursuant to General Instruction E to Form S-8, the Registrant hereby
incorporates by reference herein the information contained in the Registrant's
Registration Statement on Form S-8 (Registration No. 33-94234) as filed with the
Securities and Exchange Commission (the "Commission") on June 30, 1995.

                                    PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3.  Incorporation of Documents by Reference.
         --------------------------------------- 

     The following documents filed with the Commission are incorporated by
reference in this Registration Statement:

     (a)  Registrant's Annual Report on Form 10-K (Commission File Number 
          0-25996) for the fiscal year ended December 31, 1996, filed with the
          Commission on March 28, 1997; and

     (b)  Registrant's Quarterly Report on Form 10-Q (Commission File Number 
          0-25996) for the fiscal quarter ended March 31, 1997, filed with the
          Commission on May 12, 1997.

     All documents subsequently filed with the Commission 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 herein 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 8.  Exhibits
         --------

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

     Exhibit 4.1  Specimen certificate representing the Common Stock of the
                  Registrant (filed as Exhibit 4.1 to Registrant's Registration
                  Statement on Form S-1 (File No. 33-91694) and incorporated
                  herein by reference).

     Exhibit 4.2  Amended and Restated Certificate of Incorporation of the
                  Registrant (filed as Exhibit 3.2 to Registrant's Registration
                  Statement on Form S-1 (File No. 33-91694) and incorporated
                  herein by reference).

                                       3
Exhibit 4.3   By-laws of the Registrant, as amended and restated (filed as
                   Exhibit 3.3 to Registrant's Registration Statement on Form 
                   S-1 (File No. 33-91694) and incorporated herein by
                   reference).

     Exhibit 4.4   Second Amended and Restated 1995 Stock Plan (filed as Exhibit
                   10.2 to Registrant's Annual Report on Form 10-K for the
                   fiscal year ended December 31, 1996 and incorporated herein
                   by reference).

     Exhibit 4.5   Form of Incentive Stock Option Agreement under the Second
                   Amended and Restated 1995 Stock Plan of the Registrant.

     Exhibit 4.6   Form of Non-Qualified Stock Option Agreement under the Second
                   Amended and Restated 1995 Stock Plan of the Registrant.

     Exhibit 5.1   Opinion of Testa, Hurwitz & Thibeault, LLP.

     Exhibit 23.1  Consent of KPMG Peat Marwick LLP.

     Exhibit 23.2  Consent of Testa, Hurwitz & Thibeault, LLP (included in
                   Exhibit 5.1).

     Exhibit 24.1  Power of Attorney (included as part of the signature page to
                   this Registration Statement).

                                       4
SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, the Registrant,
TranSwitch Corporation, 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 Shelton, State of Connecticut, on this July 10,
1997.

                                    TRANSWITCH CORPORATION

                                    By: /s/ Dr. Santanu Das
                                        -------------------
                                        Dr. Santanu Das
                                        President, Chief Executive Officer

                               POWER OF ATTORNEY

     KNOW ALL PERSONS BY THESE PRESENTS, that each such person whose signature
appears below constitutes and appoints, jointly and severally, Dr. Santanu Das
and Michael F. Stauff 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 (including post-effective amendments), and to
file the same, with all 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/ Dr. Santanu Das          President, Chief Executive            July 10, 1997
---------------------------  Officer and Director        
Dr. Santanu Das              (Principal Executive Officer)
                                                          
 
/s/ Michael F. Stauff        Vice President, Chief Financial       July 10, 1997
---------------------------  Officer and Treasurer
Michael F. Stauff            (Principal Financial and Accounting
                             Officer)                            
                                                                 
/s/ Dr. Steward S. Flaschen  Director                              July 10, 1997
---------------------------  
Dr. Steward S. Flaschen
 
/s/ Dr. Charles Lee          Director                              July 10, 1997
---------------------------
Dr. Charles Lee
 
/s/ Dr. Ljubomir Micic       Director                              July 10, 1997
---------------------------
Dr. Ljubomir Micic
 
/s/ Dr. Albert E. Paladino   Director                              July 10, 1997
---------------------------  
Dr. Albert E. Paladino
INDEX TO EXHIBITS
Exhibit                      Description of Exhibit
-------                      ----------------------
Exhibit 4.1    Specimen certificate representing the Common Stock of the
               Registrant (filed as Exhibit 4.1 to Registrant's Registration
               Statement on Form S-1 (File No. 33-91694) and incorporated herein
               by reference).

Exhibit 4.2    Amended and Restated Certificate of Incorporation of the
               Registrant (filed as Exhibit 3.2 to Registrant's Registration
               Statement on Form S-1 (File No. 33-91694) and incorporated herein
               by reference).

Exhibit 4.3    By-laws of the Registrant, as amended and restated (filed as
               Exhibit 3.3 to Registrant's Registration Statement on Form S-1
               (File No. 33-91694) and incorporated herein by reference).

Exhibit 4.4    Second Amended and Restated 1995 Stock Plan (filed as Exhibit
               10.2 to Registrant's Annual Report on Form 10-K and incorporated
               herein by reference).

Exhibit 4.5    Form of Incentive Stock Option Agreement under the Second Amended
               and Restated 1995 Stock Plan of the Registrant.

Exhibit 4.6    Form of Non-Qualified Stock Option Agreement under the Second
               Amended and Restated 1995 Stock Plan of the Registrant.

Exhibit 5.1    Opinion of Testa, Hurwitz & Thibeault, LLP.

Exhibit 23.1   Consent of KPMG Peat Marwick LLP.

Exhibit 23.2   Consent of Testa, Hurwitz & Thibeault, LLP (included in 
               Exhibit 5.1).

Exhibit 24.1   Power of Attorney (included as part of the signature page to this
               Registration Statement).