SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549

                                    FORM 8-K

                                 CURRENT REPORT

     Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

                                  July 21, 2004
                               -------------------
                Date of Report (Date of earliest event reported)
                               -------------------

                                  iBASIS, INC.
                              ---------------------
               (Exact Name of Registrant as Specified in Charter)


            DELAWARE                     0-27127                04-3332534
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(State or Other Jurisdiction of        (Commission            (IRS Employer
         Incorporation)                File Number)        Identification No.)



                     20 Second Avenue, Burlington, MA 01803

            ---------------------------------------------------------
               (Address of Principal Executive Offices) (Zip Code)

                                 (781) 505-7500

              (Registrant's telephone number, including area code)
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ITEM 7. FINANCIAL STATEMENTS, PRO FORMA FINANCIAL INFORMATION AND EXHIBITS.

         (C)      EXHIBITS.
                  EXHIBIT
                  NUMBER            DESCRIPTION
                  ------------      ------------
                  Exhibit 99.1      Press Release, dated July 21, 2004

ITEM 9.  REGULATION AND DISCLOSURE.

     On July 21, 2004,  iBasis,  Inc.  (the  "Company")  issued a press  release
regarding  results for the three  months and year ended June 30, 2004. A copy of
this press release is being  furnished as Exhibit 99.1 to this Current Report on
Form 8-K. This Current Report on Form 8-K and the press release  attached hereto
are being furnished by the Company  pursuant to Item 12 of Form 8-K,  insofar as
they  disclose  historical   information  regarding  the  Company's  results  of
operations for the three months and year ended June 30, 2004. In accordance with
General  Instruction  B.6 of Form 8-K, the information in this Current Report on
Form 8-K,  including  Exhibit 99.1, shall not be deemed "filed" for the purposes
of Section 18 of the Securities  Exchange Act of 1934, as amended,  or otherwise
subject to the liability of that section, nor shall it be deemed incorporated by
reference in any filing under the Securities Act of 1933, as amended,  except as
shall be expressly set forth by specific reference in such a filing.


                                    SIGNATURE
                                    ---------

     Pursuant to the  requirements  of the Securities  Exchange Act of 1934, the
Registrant  has duly  caused  this  report  to be  signed  on its  behalf by the
undersigned hereunto duly authorized.

Date:  July 21, 2004          iBasis, INC.

                              By:  /s/  Richard Tennant
                                  ----------------------------------------
                                  Vice President, Finance and Administration
                                  And Chief Financial Officer
                                  (Principal Financial and Accounting Officer)