<PAGE>   1
              As filed with the Securities and Exchange Commission
                               on February 6, 1997

                                                           Registration No. 333-

================================================================================
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                    FORM S-8

                          REGISTRATION STATEMENT UNDER
                           THE SECURITIES ACT OF 1933

               INTERNATIONAL TELECOMMUNICATION DATA SYSTEMS, INC.
               (Exact name of issuer as specified in its charter)

                DELAWARE                                06-12959
   (State or other jurisdiction of                   (I.R.S. Employer
   incorporation or organization)                    Identification No.)
                                       
                225 HIGH RIDGE ROAD, STAMFORD, CONNECTICUT 06905
               (Address of Principal Executive Offices) (Zip Code)

                        1996 EMPLOYEE STOCK PURCHASE PLAN
                            (Full title of the plan)

                              JOHN A. BURGESS, ESQ.
                                HALE AND DORR LLP
                                 60 STATE STREET
                                BOSTON, MA 02109
                     (Name and address of agent for service)

                                 (617) 526-6000
          (Telephone number, including area code, of agent for service)

================================================================================
<TABLE>
                   CALCULATION OF REGISTRATION FEE

<CAPTION>
                            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,  200,000     $22.125(1)  $4,425,000(1)  $1,341
 $.01           shares
 par value

<FN>

-------------------------------------------------------------------------------
 (1)  Estimated solely for the purpose of calculating the registration
      fee, and based upon the average of the high and low prices of the
      Common Stock on the Nasdaq National Market on February 4, 1997 in
      accordance with Rules 457(c) and 457(h) of the Securities Act of
      1933.
</TABLE>

================================================================================


                               Page 1 of 11 pages
                          Exhibit Index begins on page 9

<PAGE>   2



PART I. INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

     The information required by Part I is included in documents sent or given
to participants in the 1996 Employee Stock Purchase Plan of International
Telecommunication Data Systems, Inc. (the "Registrant") pursuant to Rule
428(b)(1) of the Securities Act of 1933, as amended (the "Securities Act").

PART II. INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

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

     The Registrant is subject to the informational and reporting requirements
of Sections 13(a), 14, and 15(d) of the Securities Exchange Act of 1934 (as
amended, the "Exchange Act"), and in accordance therewith files reports, proxy
statements and other information with the Securities and Exchange Commission
(the "Commission"). The following documents, which are filed with the
Commission, are incorporated in this Registration Statement by reference:

          (1) The Registrant's latest annual report filed pursuant to Section
     13(a) or 15(d) of the Exchange Act or the latest prospectus filed pursuant
     to Rule 424(b) under the Securities Act that contains audited financial
     statements for the Registrant's latest fiscal year for which such
     statements have been filed.

          (2) All other reports filed pursuant to Section 13(a) or 15(d) of the
     Exchange Act since the end of the fiscal year covered by the document
     referred to in (1) above.

          (3) The description of the common stock of the Registrant, par value
     $.01 per share ("Common Stock"), contained in the Registrant's Registration
     Statement on Form 8-A filed under the Exchange Act, including any amendment
     or report filed for the purpose of updating such description.

          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 shares of Common Stock
offered hereby have been sold or which deregisters all shares of Common Stock
then remaining unsold, shall be deemed to be incorporated by reference herein
and to be part hereof from the date of the filing of such documents.

     Item 4. Description of Securities.
             -------------------------

          Not applicable.


                                       -2-

<PAGE>   3


     Item 5. Interests of Named Experts and Counsel.
             --------------------------------------

          Not applicable.

     Item 6. Indemnification
             ---------------

     Article SEVENTH of the Registrant's Certificate of Incorporation provides
that no director of the Registrant shall be personally liable for any monetary
damages for any breach of fiduciary duty as a director, except to the extent
that the Delaware General Corporation law prohibits the elimination or
limitation of liability of directors for breach of fiduciary duty.

     Article EIGHTH of the Registrant's Certificate of Incorporation provides
that a director or officer of the Registrant (a) shall be indemnified by the
Registrant against all expenses (including attorneys' fees), judgments, fines
and amounts paid in settlement incurred in connection with any litigation or
other legal proceeding (other than an action by or in the right of the
Registrant) brought against him by virtue of his position as a director or
officer of the Registrant if he acted in good faith and in a manner he
reasonably believed to be in, or not opposed to, the best interests of the
Registrant, and, with respect to any criminal action or proceeding, has no
reasonable cause to believe his conduct was unlawful and (b) shall be
indemnified by the Registrant against all expenses (including attorneys' fees)
and amounts paid in settlement incurred in connection with any action by or in
the right of the Registrant brought against him by virtue of his position as a
director or officer of the Registrant if he acted in good faith and in a manner
he reasonably believed to be in, or not opposed to, the best interests of the
Registrant, except that no indemnification shall be made with respect to any
matter as to which such person shall have been adjudged to be liable to the
Registrant, unless a court determines that, despite such adjudication but in
view of all of the circumstances, he is entitled to indemnification of such
expenses. Notwithstanding the foregoing, to the extent that a director or
officer has been successful, on the merits or otherwise, including, without
limitation, the dismissal of an action without prejudice, he is required to be
indemnified by the Registrant against all expenses (including attorneys' fees)
incurred in connection therewith. Expenses shall be advanced to a Director or
officer at his request, provided that he undertakes to repay the amount advanced
if it is ultimately determined that he is not entitled to indemnification for
such expenses.

     Indemnification is required to be made unless the Registrant determines
that the applicable standard of conduct required for indemnification has not
been met. In the event of a determination by the Registrant that the director or
officer did not meet the applicable standard of conduct required for
indemnification, or if the Registrant fails to make an indemnification payment
within 60 days after such payment is claimed by such person, such person is


                                       -3-


<PAGE>   4


permitted to petition the court to make an independent determination as to
whether such person is entitled to indemnification. As a condition precedent to
the right of indemnification, the director or officer must give the Registrant
notice of the action for which indemnity is sought and the Registrant has the
right to participate in such action or assume the defense thereof.

     Article EIGHTH of the Registrant's Certificate of Incorporation further
provides that the indemnification provided therein is not exclusive, and
provides that in the event that the Delaware General Corporation Law is amended
to expand the indemnification permitted to directors or officers the Registrant
must indemnify those persons to the full extent permitted by such law as so
amended.

     Section 145 of the Delaware General Corporation Law provides that a
corporation has the power to indemnify a director, officer, employee or agent of
the corporation and certain other persons serving at the request of the
corporation in related capacities against amounts paid and expenses incurred in
connection with an action or proceeding to which he is or is threatened to be
made a party by reason of such position, if such person shall have acted in good
faith and in a manner he reasonably believed to be in or not opposed to the best
interests of the corporation, and, in any criminal proceeding, if such person
had no reasonable cause to believe his conduct was unlawful; provided that, in
the case of actions brought by or in the right of the corporation no
indemnification shall be made with respect to any matter as to which such person
shall have been adjudged to be liable to the corporation unless and only to the
extent that the adjudicating court determines that such indemnification is
proper under the circumstances.

     The Registrant has purchased and maintains insurance coverage under a
policy insuring directors and officers of the Registrant against certain
liabilities which they may incur as directors or officers of the Registrant,
which may include coverage for liabilities arising under the Securities Act.

     Item 7. Exemption from Registration Claimed
             -----------------------------------

          Not applicable.

     Item 8. Exhibits.
             --------

          The Exhibit Index immediately preceding the exhibits is incorporated
herein by reference.

     Item 9. Undertakings.
             ------------

          1. The Registrant hereby undertakes:



                                       -4-


<PAGE>   5


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

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

          (ii) To reflect in the prospectus any facts or events arising after
     the effective date of 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; and

          (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 (i) and (ii) do not apply if the
     registration statement is on Form S-3 or Form S-8, and the information
     required to be included in a post-effective amendment by those paragraphs
     is contained in periodic reports filed by the Registrant 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, 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 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


                                       -5-


<PAGE>   6


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 in the initial bona fide offering thereof.

     3. Insofar as indemnification for liabilities arising under the Securities
Act may be permitted to directors, officers and controlling persons of the
Registrant pursuant to the foregoing provisions, or otherwise, the Registrant
has been advised that in the opinion of the Commission such indemnification is
against public policy as expressed in the Securities Act and is, therefore,
unenforceable. In the event that a claim for indemnification against such
liabilities (other than the payment by the Registrant of expenses incurred or
paid by a director, officer or controlling person of the Registrant in the
successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the Registrant will, unless in the opinion of its counsel the matter
has been settled by controlling precedent, submit to a court of appropriate
jurisdiction the question whether such indemnification by it is against public
policy as expressed in the Securities Act and will be governed by the final
adjudication of such issue.


                                       -6-


<PAGE>   7


                                   SIGNATURES

     Pursuant to the requirements of the Securities Act, the registrant
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-8 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in Stamford, Connecticut on this 5th day of February, 1997.


                                  INTERNATIONAL TELECOMMUNICATION
                                  DATA SYSTEMS, INC.



                                  By: /s/ Charles L. Bakes
                                      --------------------------- 
                                      Charles L. Bakes
                                      President and Chief
                                      Executive Officer


                                POWER OF ATTORNEY

     We, the undersigned officers and directors of International
Telecommunication Data Systems, Inc. hereby severally constitute Lewis D. Bakes,
Mark D. Spitzer and John A. Burgess, and each of them singly, our true and
lawful attorneys with full power to them, and each of them singly, to sign for
us and in our names in the capacities indicated below, the Registration
Statement on Form S-8 filed herewith and any and all subsequent amendments to
said Registration Statement, and generally to do all such things in our names
and behalf in our capacities as officers and directors to enable International
Telecommunication Data Systems, Inc. to comply with all requirements of the
Securities and Exchange Commission, hereby ratifying and confirming our
signatures as they may be signed by said attorneys, or any of them, to said
Registration Statement and any and all amendments thereto.


                                       -7-


<PAGE>   8


     Pursuant to the requirements of the Securities Act, this Registration
Statement has been signed below by the following persons in the capacities
indicated as of February 5, 1997.

       Signature                     Title
       ---------                     -----



  /s/ Charles L. Bakes        President, Chief Executive
  -------------------------   Officer and Director (Principal
  Charles L. Bakes            Executive Officer)
                              

  /s/ Mark D. Spitzer         Executive Vice President,
  -------------------------   Chief Financial Officer and
  Mark D. Spitzer             Director (Principal Financial
                              and Accounting Officer)
                              

  /s/ Lewis D. Bakes          Director
  -------------------------
  Lewis D. Bakes


  /s/ Stuart L. Bell          Director
  -------------------------
  Stuart L. Bell


  -------------------------   Director
  Michael E. Kalogris
  


                                      -8-


<PAGE>   9


                                  Exhibit Index
                                  -------------


    Exhibit
    Number       Description
    ------       -----------

       4.1       Certificate of Incorporation or Organization(1)

       4.2       By-Laws(2)

       4.3       Specimen Certificate of Common Stock of Registrant(3)

       5.1       Opinion of Hale and Dorr LLP

      23.1       Consent of Ernst & Young LLP

      23.2       Consent of Hale and Dorr LLP (included in Exhibit 5.1)

      24.1       Power of Attorney (included in the signature pages
                   of this Registration Statement)

----------
         
(1)  Incorporated herein by reference to Exhibit 3.3 to the Registrant's
     Registration Statement on Form S-1 (File No. 33-11045).

(2)  Incorporated herein by reference to Exhibit 3.4 to the Registrant's
     Registration Statement on Form S-1 (File No. 33-11045).

(3)  Incorporated herein by reference to Exhibit 4.1 to the Registrant's
     Registration Statement on Form S-1 (File No. 33-11045).
[{"type": "S-8", "sequence": "1", "description": "INTERNATIONAL TELECOMMUNICATION DATA SYSTEMS, INC.", "secsgml_size_bytes": 19126}]
{"company-data": {"conformed-name": "INTERNATIONAL TELECOMMUNICATION DATA SYSTEMS INC", "cik": "0000867889", "assigned-sic": "7371", "irs-number": "061295986", "state-of-incorporation": "CT", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-21283", "film-number": "97519590"}, "business-address": {"street1": "969 HIGH RIDGE ROAD", "street2": "STE 205", "city": "STAMFORD", "state": "CT", "zip": "06905", "phone": "2033293300"}, "mail-address": {"street1": "969 HIGH RIDGE RD", "street2": "STE 205", "city": "STAMFORD", "state": "CT", "zip": "06905"}}
1
              As filed with the Securities and Exchange Commission
                               on February 6, 1997

                                                           Registration No. 333-

================================================================================
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                    FORM S-8

                          REGISTRATION STATEMENT UNDER
                           THE SECURITIES ACT OF 1933

               INTERNATIONAL TELECOMMUNICATION DATA SYSTEMS, INC.
               (Exact name of issuer as specified in its charter)

                DELAWARE                                06-12959
   (State or other jurisdiction of                   (I.R.S. Employer
   incorporation or organization)                    Identification No.)
                                       
                225 HIGH RIDGE ROAD, STAMFORD, CONNECTICUT 06905
               (Address of Principal Executive Offices) (Zip Code)

                        1996 EMPLOYEE STOCK PURCHASE PLAN
                            (Full title of the plan)

                              JOHN A. BURGESS, ESQ.
                                HALE AND DORR LLP
                                 60 STATE STREET
                                BOSTON, MA 02109
                     (Name and address of agent for service)

                                 (617) 526-6000
          (Telephone number, including area code, of agent for service)

================================================================================

                   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,  200,000     $22.125(1)  $4,425,000(1)  $1,341
 $.01           shares
 par value
-------------------------------------------------------------------------------
 (1)  Estimated solely for the purpose of calculating the registration
      fee, and based upon the average of the high and low prices of the
      Common Stock on the Nasdaq National Market on February 4, 1997 in
      accordance with Rules 457(c) and 457(h) of the Securities Act of
      1933.
================================================================================

                               Page 1 of 11 pages
                          Exhibit Index begins on page 9
2

PART I. INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

     The information required by Part I is included in documents sent or given
to participants in the 1996 Employee Stock Purchase Plan of International
Telecommunication Data Systems, Inc. (the "Registrant") pursuant to Rule
428(b)(1) of the Securities Act of 1933, as amended (the "Securities Act").

PART II. INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

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

     The Registrant is subject to the informational and reporting requirements
of Sections 13(a), 14, and 15(d) of the Securities Exchange Act of 1934 (as
amended, the "Exchange Act"), and in accordance therewith files reports, proxy
statements and other information with the Securities and Exchange Commission
(the "Commission"). The following documents, which are filed with the
Commission, are incorporated in this Registration Statement by reference:

          (1) The Registrant's latest annual report filed pursuant to Section
     13(a) or 15(d) of the Exchange Act or the latest prospectus filed pursuant
     to Rule 424(b) under the Securities Act that contains audited financial
     statements for the Registrant's latest fiscal year for which such
     statements have been filed.

          (2) All other reports filed pursuant to Section 13(a) or 15(d) of the
     Exchange Act since the end of the fiscal year covered by the document
     referred to in (1) above.

          (3) The description of the common stock of the Registrant, par value
     $.01 per share ("Common Stock"), contained in the Registrant's Registration
     Statement on Form 8-A filed under the Exchange Act, including any amendment
     or report filed for the purpose of updating such description.

          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 shares of Common Stock
offered hereby have been sold or which deregisters all shares of Common Stock
then remaining unsold, shall be deemed to be incorporated by reference herein
and to be part hereof from the date of the filing of such documents.

     Item 4. Description of Securities.
             -------------------------

          Not applicable.

                                       -2-
3

     Item 5. Interests of Named Experts and Counsel.
             --------------------------------------

          Not applicable.

     Item 6. Indemnification
             ---------------

     Article SEVENTH of the Registrant's Certificate of Incorporation provides
that no director of the Registrant shall be personally liable for any monetary
damages for any breach of fiduciary duty as a director, except to the extent
that the Delaware General Corporation law prohibits the elimination or
limitation of liability of directors for breach of fiduciary duty.

     Article EIGHTH of the Registrant's Certificate of Incorporation provides
that a director or officer of the Registrant (a) shall be indemnified by the
Registrant against all expenses (including attorneys' fees), judgments, fines
and amounts paid in settlement incurred in connection with any litigation or
other legal proceeding (other than an action by or in the right of the
Registrant) brought against him by virtue of his position as a director or
officer of the Registrant if he acted in good faith and in a manner he
reasonably believed to be in, or not opposed to, the best interests of the
Registrant, and, with respect to any criminal action or proceeding, has no
reasonable cause to believe his conduct was unlawful and (b) shall be
indemnified by the Registrant against all expenses (including attorneys' fees)
and amounts paid in settlement incurred in connection with any action by or in
the right of the Registrant brought against him by virtue of his position as a
director or officer of the Registrant if he acted in good faith and in a manner
he reasonably believed to be in, or not opposed to, the best interests of the
Registrant, except that no indemnification shall be made with respect to any
matter as to which such person shall have been adjudged to be liable to the
Registrant, unless a court determines that, despite such adjudication but in
view of all of the circumstances, he is entitled to indemnification of such
expenses. Notwithstanding the foregoing, to the extent that a director or
officer has been successful, on the merits or otherwise, including, without
limitation, the dismissal of an action without prejudice, he is required to be
indemnified by the Registrant against all expenses (including attorneys' fees)
incurred in connection therewith. Expenses shall be advanced to a Director or
officer at his request, provided that he undertakes to repay the amount advanced
if it is ultimately determined that he is not entitled to indemnification for
such expenses.

     Indemnification is required to be made unless the Registrant determines
that the applicable standard of conduct required for indemnification has not
been met. In the event of a determination by the Registrant that the director or
officer did not meet the applicable standard of conduct required for
indemnification, or if the Registrant fails to make an indemnification payment
within 60 days after such payment is claimed by such person, such person is

                                       -3-
4

permitted to petition the court to make an independent determination as to
whether such person is entitled to indemnification. As a condition precedent to
the right of indemnification, the director or officer must give the Registrant
notice of the action for which indemnity is sought and the Registrant has the
right to participate in such action or assume the defense thereof.

     Article EIGHTH of the Registrant's Certificate of Incorporation further
provides that the indemnification provided therein is not exclusive, and
provides that in the event that the Delaware General Corporation Law is amended
to expand the indemnification permitted to directors or officers the Registrant
must indemnify those persons to the full extent permitted by such law as so
amended.

     Section 145 of the Delaware General Corporation Law provides that a
corporation has the power to indemnify a director, officer, employee or agent of
the corporation and certain other persons serving at the request of the
corporation in related capacities against amounts paid and expenses incurred in
connection with an action or proceeding to which he is or is threatened to be
made a party by reason of such position, if such person shall have acted in good
faith and in a manner he reasonably believed to be in or not opposed to the best
interests of the corporation, and, in any criminal proceeding, if such person
had no reasonable cause to believe his conduct was unlawful; provided that, in
the case of actions brought by or in the right of the corporation no
indemnification shall be made with respect to any matter as to which such person
shall have been adjudged to be liable to the corporation unless and only to the
extent that the adjudicating court determines that such indemnification is
proper under the circumstances.

     The Registrant has purchased and maintains insurance coverage under a
policy insuring directors and officers of the Registrant against certain
liabilities which they may incur as directors or officers of the Registrant,
which may include coverage for liabilities arising under the Securities Act.

     Item 7. Exemption from Registration Claimed
             -----------------------------------

          Not applicable.

     Item 8. Exhibits.
             --------

          The Exhibit Index immediately preceding the exhibits is incorporated
herein by reference.

     Item 9. Undertakings.
             ------------

          1. The Registrant hereby undertakes:

                                       -4-
5

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

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

          (ii) To reflect in the prospectus any facts or events arising after
     the effective date of 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; and

          (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 (i) and (ii) do not apply if the
     registration statement is on Form S-3 or Form S-8, and the information
     required to be included in a post-effective amendment by those paragraphs
     is contained in periodic reports filed by the Registrant 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, 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 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

                                       -5-
6

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 in the initial bona fide offering thereof.

     3. Insofar as indemnification for liabilities arising under the Securities
Act may be permitted to directors, officers and controlling persons of the
Registrant pursuant to the foregoing provisions, or otherwise, the Registrant
has been advised that in the opinion of the Commission such indemnification is
against public policy as expressed in the Securities Act and is, therefore,
unenforceable. In the event that a claim for indemnification against such
liabilities (other than the payment by the Registrant of expenses incurred or
paid by a director, officer or controlling person of the Registrant in the
successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the Registrant will, unless in the opinion of its counsel the matter
has been settled by controlling precedent, submit to a court of appropriate
jurisdiction the question whether such indemnification by it is against public
policy as expressed in the Securities Act and will be governed by the final
adjudication of such issue.

                                       -6-
7

                                   SIGNATURES

     Pursuant to the requirements of the Securities Act, the registrant
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-8 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in Stamford, Connecticut on this 5th day of February, 1997.

                                  INTERNATIONAL TELECOMMUNICATION
                                  DATA SYSTEMS, INC.

                                  By: /s/ Charles L. Bakes
                                      --------------------------- 
                                      Charles L. Bakes
                                      President and Chief
                                      Executive Officer

                                POWER OF ATTORNEY

     We, the undersigned officers and directors of International
Telecommunication Data Systems, Inc. hereby severally constitute Lewis D. Bakes,
Mark D. Spitzer and John A. Burgess, and each of them singly, our true and
lawful attorneys with full power to them, and each of them singly, to sign for
us and in our names in the capacities indicated below, the Registration
Statement on Form S-8 filed herewith and any and all subsequent amendments to
said Registration Statement, and generally to do all such things in our names
and behalf in our capacities as officers and directors to enable International
Telecommunication Data Systems, Inc. to comply with all requirements of the
Securities and Exchange Commission, hereby ratifying and confirming our
signatures as they may be signed by said attorneys, or any of them, to said
Registration Statement and any and all amendments thereto.

                                       -7-
8

     Pursuant to the requirements of the Securities Act, this Registration
Statement has been signed below by the following persons in the capacities
indicated as of February 5, 1997.

       Signature                     Title
       ---------                     -----

  /s/ Charles L. Bakes        President, Chief Executive
  -------------------------   Officer and Director (Principal
  Charles L. Bakes            Executive Officer)
                              

  /s/ Mark D. Spitzer         Executive Vice President,
  -------------------------   Chief Financial Officer and
  Mark D. Spitzer             Director (Principal Financial
                              and Accounting Officer)
                              

  /s/ Lewis D. Bakes          Director
  -------------------------
  Lewis D. Bakes

  /s/ Stuart L. Bell          Director
  -------------------------
  Stuart L. Bell

  -------------------------   Director
  Michael E. Kalogris
  

                                      -8-
9

                                  Exhibit Index
                                  -------------

    Exhibit
    Number       Description
    ------       -----------

       4.1       Certificate of Incorporation or Organization(1)

       4.2       By-Laws(2)

       4.3       Specimen Certificate of Common Stock of Registrant(3)

       5.1       Opinion of Hale and Dorr LLP

      23.1       Consent of Ernst & Young LLP

      23.2       Consent of Hale and Dorr LLP (included in Exhibit 5.1)

      24.1       Power of Attorney (included in the signature pages
                   of this Registration Statement)

----------
         
(1)  Incorporated herein by reference to Exhibit 3.3 to the Registrant's
     Registration Statement on Form S-1 (File No. 33-11045).

(2)  Incorporated herein by reference to Exhibit 3.4 to the Registrant's
     Registration Statement on Form S-1 (File No. 33-11045).

(3)  Incorporated herein by reference to Exhibit 4.1 to the Registrant's
     Registration Statement on Form S-1 (File No. 33-11045).