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                                                                    EXHIBIT 99.1

                                  CERTIFICATION

I, Michael S. Liss, certify that:

1. I have reviewed this quarterly report on Form 10-Q of FiberNet Telecom Group,
Inc.;

2. Based on my knowledge, this quarterly report does not contain any untrue
statement of a material fact or omit to state a material fact necessary to make
the statements made, in light of the circumstances under which such statements
were made, not misleading with respect to the period covered by this quarterly
report;

3. Based on my knowledge, the financial statements, and other financial
information included in this quarterly report, fairly present in all material
respects the financial condition, results of operations and cash flows of the
registrant as of, and for, the periods presented in this quarterly report;

4. The registrant's other certifying officers and I are responsible for
establishing and maintaining disclosure controls and procedures (as defined in
Exchange Act Rules 13a-14 and 15d-14) for the registrant and we have:

     a)   designed such disclosure controls and procedures to ensure that
          material information relating to the registrant, including its
          consolidated subsidiaries, is made known to us by others within those
          entities, particularly during the period in which this quarterly
          report is being prepared;

     b)   evaluated the effectiveness of the registrant's disclosure controls
          and procedures as of a date within 90 days prior to the filing date of
          this quarterly report (the "Evaluation Date"); and

     c)   presented in this quarterly report our conclusions about the
          effectiveness of the disclosure controls and procedures based on our
          evaluation as of the Evaluation Date;

5. The registrant's other certifying officers and I have disclosed, based on our
most recent evaluation, to the registrant's auditors and the audit committee of
the registrant's board of directors (or persons performing the equivalent
functions):

     a)   all significant deficiencies in the design or operation of internal
          controls which could adversely affect the registrant's ability to
          record, process, summarize and report financial data and have
          identified for the registrant's auditors any material weaknesses in
          internal controls; and

     b)   any fraud, whether or not material, that involves management or other
          employees who have a significant role in the registrant's internal
          controls; and

6. The registrant's other certifying officers and I have indicated in this
quarterly report whether there were significant changes in internal controls or
in other factors that could significantly affect internal controls subsequent to
the date of our most recent evaluation, including any corrective actions with
regard to significant deficiencies and material weaknesses.


Date: May 12, 2003
                                                       /s/ Michael S. Liss
                                                   -----------------------------
                                                          Michael S. Liss
                                                           President and
                                                      Chief Executive Officer
                                                   (Principal Executive Officer)