Exhibit 10.72

THIRD LOAN MODIFICATION AGREEMENT

This Third Loan Modification Agreement (this "Loan Modification Agreement") is entered into as of January 4, 2005, by and between SILICON VALLEY
BANK, a California-chartered bank, with its principal place of business at 3003 Tasman Drive, Santa Clara, California 95054 and
with a loan production office located at One Newton Executive Park, Suite 200, 2221 Washington Street, Newton, Massachusetts 02462, doing business under the name "Silicon Valley East" ("Bank") and IBASIS, INC., a Delaware corporation with its chief executive office located at 20 Second Avenue, Burlington, Massachusetts 01803 ("Borrower").

1.DESCRIPTION OF EXISTING INDEBTEDNESS AND OBLIGATIONS.Among other indebtedness and obligations which may be owing by
Borrower to Bank, Borrower is indebted to Bank pursuant to a loan arrangement dated as of December 29, 2003 evidenced by, among other documents, instruments and agreements, a certain Amended
and Restated Loan and Security Agreement dated as of December 29, 2003, as affected and amended by a certain Consent, Waiver and Amendment Agreement dated as of June 18, 2004, as further
amended by a certain First Loan Modification Agreement dated as of June 30, 2004, and as further amended by a certain Second Loan Modification Agreement dated as of September 30, 2004
(as amended, the "Loan Agreement"). Capitalized terms used but not otherwise defined herein shall have the same meaning as in the Loan Agreement.

2.DESCRIPTION OF COLLATERAL.Repayment of the Obligations is secured by the Collateral as described in the Loan Agreement and
is secured by the Intellectual Property Collateral as described in a certain Intellectual Property Security Agreement dated December 30, 2002 (the "IP Security Agreement") (together with any
other collateral security granted to Bank, the "Security Documents").

Hereinafter,
the Security Documents, together with all other documents evidencing or securing the Obligations shall be referred to as the "Existing Loan Documents".

3.DESCRIPTION OF CHANGE IN TERMS.

Modifications to Loan Agreement







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4.FEES.Borrower shall pay to Bank a modification fee equal to Fifty-Seven Thousand Five Hundred Dollars ($57,500.00), which
fee shall be earned as of the date hereof and shall be payable as follows: (i) Thirty-Two Thousand Five Hundred Dollars ($32,500.00) on the date hereof and (ii) Twenty-Five Thousand
dollars ($25,000.00) on the sooner to occur of (x) the occurrence of an Event of Default, (y) the early termination of the Loan Agreement, or (z) January 5, 2006. Borrower
shall also reimburse Bank for all reasonable legal fees and expenses incurred in connection with this amendment to the Existing Loan Documents.

5.RATIFICATION OF IP SECURITY AGREEMENT.Borrower hereby ratifies, confirms and reaffirms, all and singular, the terms and
conditions of the IP Security Agreement, and acknowledges, confirms and agrees that the IP Security Agreement contains an accurate and complete (in all material respects) listing of all Intellectual
Property Collateral as defined therein, and shall remain in full force and effect.

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6.RATIFICATION OF PERFECTION CERTIFICATE.Borrower hereby ratifies, confirms and reaffirms, all and singular, the terms and
disclosures contained in a certain Perfection Certificate dated as of December 30, 2002 between Borrower and Bank, and acknowledges, confirms and agrees the disclosures and information Borrower
provided to Bank in the Perfection Certificate have not changed in any material respects, as of the date hereof.

7.CONSISTENT CHANGES.The Existing Loan Documents are hereby amended wherever necessary to reflect the changes described
above.

8.NO DEFENSES OF BORROWER.Borrower hereby acknowledges and agrees that Borrower has no offsets, defenses, claims, or
counterclaims against Bank with respect to the Obligations, or otherwise, and that if Borrower now has, or ever did have, any offsets, defenses, claims, or counterclaims against Bank, whether known or
unknown, at law or in equity, all of them are hereby expressly WAIVED and Borrower hereby RELEASES Bank from any liability thereunder, in each case to the extent that any of the foregoing arises from
any action or failure to act on or prior to the date hereof under or in respect of the Loan Agreement or any of the other Existing Loan Documents; provided, however, that the waiver and release
contained herein shall not apply to any act or omission constituting gross negligence or willful misconduct on behalf of Bank which is discovered by Borrower after the date hereof.

9.CONTINUING VALIDITY.Borrower understands and agrees that in modifying the existing Obligations, Bank is relying upon
Borrower's representation, warranties, and agreements, as set forth in the Existing Loan Documents. Except as expressly modified pursuant to this Loan Modification Agreement, the terms of the Existing
Loan Documents remain unchanged and in full force and effect and Borrower hereby ratifies, confirms, and reaffirms all the terms and conditions thereof. Borrower confirms that the indebtedness secured
by the Security Documents includes, without limitation, the Obligations. Bank's agreement to modifications to the existing Obligations pursuant to this Loan Modification Agreement in no way shall
obligate Bank to make any future modifications to the Obligations. Nothing in this Loan Modification Agreement shall constitute a satisfaction of the Obligations. It is the intention of Bank and
Borrower to retain as liable parties all makers of Existing Loan Documents, unless the party is expressly released by Bank in writing. No maker will be released by virtue of this Loan Modification
Agreement.

10.COUNTERSIGNATURE.This Loan Modification Agreement shall become effective only when it shall have been executed by
Borrower and Bank (provided, however, in no event shall this Loan Modification Agreement become effective until signed by an officer of Bank in California).

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This
Loan Modification Agreement is executed as a sealed instrument under the laws of the Commonwealth of Massachusetts as of the date first written above.

BORROWER:

BANK:IBASIS, INC.

SILICON VALLEY BANK, doing business as
SILICON VALLEY EASTBy:
/s/OFER GNEEZY

By:
/s/MICHAEL D. SINCLAIRName:
Ofer Gneezy

Name:
Michael D. SinclairTitle:
President

Title:
Vice PresidentSILICON VALLEY BANKBy:
/s/JACQUELIN LEName:
Jacquelin LeTitle:
Operations Supervisor(signed in Santa Clara County, California)


The
undersigned, IBASIS GLOBAL, INC., ratifies, confirms and reaffirms, all and singular, the terms and conditions of a certain Unconditional Guaranty dated December 29, 2003
executed and delivered by the undersigned and a certain Security Agreement dated December 29, 2003 executed and delivered by the undersigned and acknowledges, confirms and agrees that the said
Unconditional Guaranty and Security Agreement shall remain in full force and effect and shall in no way be limited by the execution of this Loan Modification Agreement, or any other documents,
instruments and/or agreements executed and/or delivered in connection herewith.

IBASIS GLOBAL, INC.By:
/s/OFER GNEEZYName:
Ofer GneezyTitle:
President


The
undersigned, IBASIS SECURITIES CORPORATION, ratifies, confirms and reaffirms, all and singular, the terms and conditions of a certain Unconditional Guaranty dated December 29,
2003 executed and delivered by the undersigned and a certain Security Agreement dated December 29, 2003 executed and delivered by the undersigned and acknowledges, confirms and agrees that the
said Unconditional Guaranty and Security Agreement shall remain in full force and effect and shall in no way be limited by the execution of this Loan Modification Agreement, or any other documents,
instruments and/or agreements executed and/or delivered in connection herewith.

IBASIS SECURITIES CORPORATIONBy:
/s/OFER GNEEZYName:
Ofer GneezyTitle:
President


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