Exhibit 31.1

MACK-CALI REALTY, L.P.

Certification

I, Mitchell E. Hersh,  President and
Chief Executive Officer of Mack-Cali Realty  Corporation,  the general partner of
Mack-Cali Realty, L.P., certify that:

|1. | I
have reviewed this quarterly report on Form 10-Q of Mack-Cali Realty, L.P.;
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|2. | Based
on my knowledge, this 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
report;
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|3. | Based
on my knowledge, the financial statements, and other financial information
               included in this 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 report;
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|4. | The
registrants other certifying officer and I are responsible for
               establishing and maintaining disclosure controls and procedures (as
defined in                Exchange Act Rules 13a-15(e) and 15d-15(e)) for the registrant
and have:
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| | a) | Designed
such disclosure controls and procedures, or caused such disclosure
               controls and procedures to be designed under our supervision, 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 report is being
prepared;
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| | b) | Evaluated
the effectiveness of the registrants disclosure controls and
               procedures and presented in this report our conclusions about the
effectiveness                of the disclosure controls and procedures, as of the end of
the period covered                by this report based on such evaluation; and
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| | c) | Disclosed
in this report any change in the registrants internal control                over
financial reporting that occurred during the registrants most recent
               fiscal quarter (the registrants fourth fiscal quarter in the case of
an                annual report) that has materially affected, or is reasonably likely to
               materially affect, the registrants internal control over financial
               reporting; and
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|5. | The
registrants other certifying officer and I have disclosed, based on
               our most recent evaluation of internal control over financial reporting,
to the                registrants auditors and the audit committee of the registrants
               board of directors (or persons performing the equivalent functions):
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| | a) | All
significant deficiencies and material weaknesses in the design or operation
               of internal control over financial reporting which are reasonably likely
to                adversely affect the registrants ability to record, process,
summarize and                report financial information; and
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| | b) | Any
fraud, whether or not material, that involves management or other employees
               who have a significant role in the registrants internal control over
               financial reporting.
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|Date:  August 6, 2004 |  | By:   /s/ Mitchell E. Hersh
Mitchell E. HershPresident and Chief Executive Officer    of Mack-Cali Realty Corporation,   the general partner of Mack-Cali    Realty, L.P.
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