**Exhibit      31.1**

**MACK-CALI      REALTY, L.P.**

**Certification**

| 1.   | I              have reviewed this annual report on Form 10-K 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)) and internal              control over financial reporting (as defined in Exchange Act Rules              13a-15(f) and 15d-15(f)) 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)   | Designed              such internal control over financial reporting, or caused such internal              control over financial reporting to be designed under our supervision,              to              provide reasonable assurance regarding the reliability of financial              reporting and the preparation of financial statements for external              purposes in accordance with generally accepted accounting              principles; |
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| c)   | 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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| d)   | 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: February                21, 2007 | By:    | /s/                Mitchell E. Hersh             |
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|                                        |   | Mitchell                E. Hersh                                                                             |
|                                        |   | President                and Chief Executive Officer                                                         |
|                                        |   | of                Mack-Cali Realty Corporation,                                                              |
|                                        |   | the                general partner of Mack-Cali Realty, L.P.                                                 |