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                                                                     Exhibit 4.1

         AMENDMENT ("Amendment") dated as of June 14, 2002 between FIBERNET
TELECOM GROUP, INC. ("Company") and SDS MERCHANT FUND, L.P. ("SDS") to that
certain Promissory Note dated as of March 14, 2002 (the "Note") by and between
the Company and SDS.

         WHEREAS, pursuant to Section 10 of the Note, the Company and SDS may
amend the Note; and

         WHEREAS, the Company and SDS wish to amend the Note.

         NOW, THEREFORE, the parties agree as follows:

         Section 1. Definitions. Capitalized terms used and not otherwise
defined herein shall have the meanings ascribed to such terms in the Note.

         Section 2. Agreement to Amend. Pursuant to Section 10 of the Note, the
Company and SDS hereby agree to amend the Note as provided herein.

         Section 3.  Amendment.

                  (a) Section 1(a)(i) is hereby amended and restated in its
entirety to read as follows:

                  "June 28, 2002, unless SDS receives written confirmation (in
         form of an officer's certificate) from the Company that the Company has
         received equity commitments in an amount of not less than $9,750,000
         and such written confirmation is in form and substance satisfactory to
         Deutsche Bank AG New York Branch, as administrative agent to the
         Company's Amended and Restated Credit Agreement dated as of February 9,
         2001 in its sole discretion, in which case July 12, 2002;"

                  (b) Section 4(c) is hereby amended and restated in its
entirety to read as follows:

                  "the Proposed Financing shall fail to have been consummated by
         July 12, 2002; or"

         Section 4. Governing Law. This Amendment shall be governed by and
construed in accordance with the laws of the State of New York, without giving
effect to the choice of law provisions.

         Section 5. Successors and Assigns. This Amendment shall bind and inure
to the benefit of the parties and their respective successors and assigns,
transferees, legal representatives and heirs.

         Section 6. Headings. The headings of this Amendment have been inserted
for convenience of reference only and shall not be deemed to be a part of this
Amendment.

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         Section 7. Entire Agreement. This Amendment and the other writings
referred to herein or delivered pursuant hereto contain the entire agreement
among the parties hereto with respect to the subject matter hereof and supersede
all prior and contemporaneous agreements and understandings with respect
thereto.

         Section 8. Counterparts. This Amendment may be executed in any number
of counterparts, and each such counterpart shall be deemed to be an original
instrument, but all such counterparts together shall constitute but one
agreement.

                                   * * * * *

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         IN WITNESS WHEREOF, the parties have executed this Amendment as of the
date first written above.

                                FIBERNET TELECOM GROUP, INC.

                                By: /s/ Michael S. Liss
                                    --------------------------------------------
                                    Name:  Michael S. Liss
                                    Title: President and Chief Executive Officer



                                SDS MERCHANT FUND, L.P.

                                By:  SDS Capital Partners, LLC
                                Its: General Partner

                                By: /s/ Steve Derby
                                    --------------------------------------------
                                    Name:  Steve Derby
                                    Title: Managing Partner