Exhibit 21

|Subsidiary                                        |  | State of
Incorporation
or Organization
|------------------------------------------------- |  | --------------------------------------
|3 SKY REALTY L.L.C.                               |  | NY                                    
|5 GREENTREE REALTY L.L.C.                         |  | NJ                                    
|5/6 SKYLINE REALTY L.L.C.                         |  | NY                                    
|9 CAMPUS REALTY L.L.C.                            |  | NJ                                    
|11 COMMERCE DRIVE ASSOCIATES L.L.C.               |  | NJ                                    
|12 SKYLINE ASSOCIATES L.L.C.                      |  | NY                                    
|14/16 SKYLINE REALTY L.L.C.                       |  | NY                                    
|25 COMMERCE REALTY L.L.C.                         |  | NJ                                    
|105 EISENHOWER REALTY L.L.C.                      |  | NJ                                    
|120 PASSAIC STREET LLC                            |  | NJ                                    
|1717 REALTY ASSOCIATES L.L.C.                     |  | NJ                                    
|20 COMMERCE DRIVE ASSOCIATES L.L.C.               |  | NJ                                    
|250 CORPORATE REALTY L.L.C.                       |  | NY                                    
|300 TICE REALTY ASSOCIATES L.L.C.                 |  | NJ                                    
|300 HORIZON ROAD REALTY L.L.C.                    |  | NJ                                    
|400 RELLA REALTY ASSOCIATES L.L.C.                |  | NY                                    
|500 COLUMBIA TURNPIKE ASSOCIATES L.L.C.           |  | NJ                                    
|600 HORIZON CENTER L.L.C.                         |  | NJ                                    
|600 PARSIPPANY ASSOCIATES L.L.C.                  |  | NJ                                    
|4 GATEHALL REALTY L.L.C.                          |  | NJ                                    
|78 PINSON PARTNERS L.L.C.                         |  | NJ                                    
|795 FOLSOM REALTY ASSOCIATES L.P.                 |  | CA                                    
|1266 SOUNDVIEW REALTY L.L.C.                      |  | CT                                    
|AIRPORT PROPERTIES ASSOCIATES LLC                 |  | NJ                                    
|BMP MOORESTOWN REALTY L.L.C.                      |  | NJ                                    
|BMP SOUTH REALTY L.L.C.                           |  | NJ                                    
|BRIDGE PLAZA ASSOCIATES L.L.C.                    |  | NJ                                    
|C.W. ASSOCIATES L.L.C.                            |  | NJ                                    
|CAL-HARBOR II & III URBAN RENEWAL ASSOCIATES L.P. |  | NJ                                    
|CAL-HARBOR IV URBAN RENEWAL ASSOCIATES L.P.       |  | NJ                                    
|CAL-HARBOR V LEASING ASSOCIATES L.L.C.            |  | NJ                                    
|CAL-HARBOR V URBAN RENEWAL ASSOCIATES L.P.        |  | NJ                                    
|                                                  |  |                                       

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|CAL-HARBOR VI URBAN RENEWAL ASSOCIATES L.P.                |  | NJ
|---------------------------------------------------------- |  | --
|CAL-HARBOR VII LEASING ASSOCIATES L.L.C.                   |  | NJ
|CAL-HARBOR VII URBAN RENEWAL ASSOCIATES L.P.               |  | NJ
|CAL-TREE REALTY ASSOCIATES L.P.                            |  | PA
|CALI HARBORSIDE (FEE) ASSOCIATES L.P.                      |  | NJ
|CALI HARBORSIDE PLAZA I (FEE) ASSOCIATES L.P.              |  | NJ
|CENTURY PLAZA ASSOCIATES L.L.C.                            |  | NJ
|CLEARBROOK ROAD ASSOCIATES L.L.C.                          |  | NY
|COLLEGE ROAD REALTY L.L.C.                                 |  | NJ
|COMMERCENTER REALTY ASSOCIATES L.L.C.                      |  | NJ
|CROSS WESTCHESTER REALTY ASSOCIATES L.L.C.                 |  | NY
|CWLT ROSELAND EXCHANGE L.L.C.                              |  | NJ
|D.B.C. REALTY L.L.C.                                       |  | NJ
|ELMSFORD REALTY ASSOCIATES L.L.C.                          |  | NY
|EMPIRE STATE VEHICLE LEASING L.L.C.                        |  | NY
|FIVE SENTRY REALTY ASSOCIATES L.P.                         |  | PA
|GARDEN STATE VEHICLE LEASING L.L.C.                        |  | NJ
|GROVE STREET ASSOCIATES OF JERSEY CITY LIMITED PARTNERSHIP |  | NJ
|HORIZON CENTER REALTY ASSOCIATES L.L.C.                    |  | NJ
|HORIZON CENTER REALTY L.L.C.                               |  | NJ
|JUMPING BROOK REALTY ASSOCIATES L.L.C.                     |  | NJ
|KEMBLE-MORRIS, LLC                                         |  | NJ
|KEYSTONE VEHICLE LEASING L.L.C.                            |  | PA
|LINWOOD REALTY L.L.C.                                      |  | NJ
|LITTLETON REALTY ASSOCIATES L.L.C.                         |  | NJ
|M-C CALIFORNIA SERVICES, INC.                              |  | DE
|M-C CAPITOL ASSOCIATES L.L.C.                              |  | DE
|M-C HARSIMUS PARTNERS L.L.C.                               |  | NJ
|M-C PENN MANAGEMENT TRUST                                  |  | MD
|M-C PROPERTIES CO. REALTY L.L.C.                           |  | NJ
|M-C ROCKLAND PARTNERS L.P.                                 |  | NY
|M-C TEXAS MANAGEMENT L.P.                                  |  | TX
|MACK-CALI ADVANTAGE SERVICES CORPORATION                   |  | DE
|MACK-CALI AIRPORT REALTY ASSOCIATES L.P.                   |  | PA
|                                                           |  |   

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|MACK-CALI B PROPERTIES, L.L.C.                   |  | NJ
|------------------------------------------------ |  | --
|MACK-CALI BRIDGEWATER CO., L.P.                  |  | NJ
|MACK-CALI BUILDING V ASSOCIATES L.L.C.           |  | NJ
|MACK-CALI CALIFORNIA DEVELOPMENT ASSOCIATES L.P. |  | CA
|MACK-CALI CALIFORNIA PARTNERS L.P.               |  | CA
|MACK-CALI CAMPUS REALTY L.L.C.                   |  | NJ
|MACK-CALI CHESTNUT RIDGE, L.L.C.                 |  | NJ
|MACK-CALI CW REALTY ASSOCIATES L.L.C.            |  | NY
|MACK-CALI D.C. MANAGEMENT CORP                   |  | DE
|MACK-CALI E-COMMERCE L.L.C.                      |  | DE
|MACK-CALI EAST LAKEMONT L.L.C.                   |  | NJ
|MACK-CALI F PROPERTIES L.P.                      |  | NJ
|MACK-CALI GLENDALE LIMITED PARTNERSHIP           |  | AZ
|MACK-CALI MID-WEST REALTY ASSOCIATES L.L.C.      |  | NY
|MACK-CALI MORRIS REALTY L.L.C.                   |  | NJ
|MACK-CALI NORTH HILLS L.L.C.                     |  | NY
|MACK-CALI PENNSYLVANIA REALTY ASSOCIATES L.P.    |  | PA
|MACK-CALI PROPERTIES CO. #3 L.P.                 |  | NJ
|MACK-CALI PROPERTIES CO. NO. 11, L.P.            |  | NY
|MACK-CALI PROPERTY TRUST                         |  | MD
|MACK-CALI SERVICES, INC.                         |  | NJ
|MACK-CALI SO. WEST REALTY ASSOCIATES L.L.C.      |  | NY
|MACK-CALI STAMFORD REALTY ASSOCIATES, L.P.       |  | CT
|MACK-CALI SUB XV, TRUST                          |  | MD
|MACK-CALI TAXTER ASSOCIATES L.L.C.               |  | NY
|MACK-CALI TEXAS PROPERTY L.P.                    |  | TX
|MACK-CALI TRS HOLDING CORPORATION                |  | DE
|MACK-CALI WILLOWBROOK COMPANY L.P.               |  | NJ
|MACK-CALI WOODBRIDGE II L.P.                     |  | NJ
|MACK-CALI WP REALTY ASSOCIATES L.L.C.            |  | NY
|MACK-CALI-R COMPANY NO. 1 L.P.                   |  | NJ
|MANHASSET ASSOCIATES L.L.C.                      |  | NY
|MAPLE 4 CAMPUS REALTY L.L.C.                     |  | NJ
|MAPLE 6 CAMPUS REALTY L.L.C.                     |  | NJ
|                                                 |  |   

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|MARTIN AVENUE REALTY ASSOCIATES L.L.C.               |  | NY
|---------------------------------------------------- |  | --
|MC-CAP L.L.C.                                        |  | DE
|MID-WESTCHESTER REALTY ASSOCIATES L.L.C.             |  | NY
|MONMOUTH/ATLANTIC REALTY ASSOCIATES L.L.C.           |  | NJ
|MOORESTOWN REALTY ASSOCIATES L.L.C.                  |  | NJ
|MORRISTOWN TEN                                       |  | NJ
|MOUNT AIRY REALTY ASSOCIATES L.L.C.                  |  | NJ
|MOUNTAINVIEW REALTY L.L.C.                           |  | NJ
|OFFICE ASSOCIATES L.L.C.                             |  | NJ
|ONE SYLVAN REALTY, L.L.C.                            |  | NJ
|PA UTILIPRO SOLUTIONS TRUST                          |  | MD
|PARSIPPANY CAMPUS REALTY ASSOCIATES L.L.C.           |  | NJ
|PHELAN REALTY ASSOCIATES L.P.                        |  | CA
|PLAZA VIII & IX ASSOCIATES L.L.C.                    |  | NJ
|PLAZA X LEASING ASSOCIATES L.L.C.                    |  | NJ
|PLAZA X REALTY L.L.C.                                |  | NJ
|PLAZA X URBAN RENEWAL ASSOCIATES L.L.C.              |  | NJ
|PRINCETON CORPORATE CENTER REALTY ASSOCIATES L.L.C.  |  | NJ
|PRINCETON OVERLOOK REALTY L.L.C.                     |  | NJ
|ROSELAND II L.L.C.                                   |  | NJ
|ROSELAND OWNERS ASSOCIATES L.L.C.                    |  | NJ
|SENTRY PARK WEST L.L.C.                              |  | PA
|SHELTON REALTY ASSOCIATES L.P.                       |  | CT
|SIX COMMERCE DRIVE ASSOCIATES L.L.C.                 |  | NJ
|SKYLINE REALTY L.L.C.                                |  | NY
|SO. WESTCHESTER REALTY ASSOCIATES L.L.C.             |  | NY
|STEVENS AIRPORT REALTY ASSOCIATES L.P.               |  | PA
|SYLVAN 701 PARTNERS L.L.C.                           |  | NJ
|SYLVAN 704 PARTNERS L.L.C.                           |  | NJ
|SYLVAN/CAMPUS REALTY ASSOCIATES L.L.C.               |  | NJ
|TALLEYRAND REALTY ASSOCIATES L.L.C.                  |  | NY
|THE HORIZON CENTER PROPERTY OWNERS ASSOCIATION, INC. |  | NJ
|TRIAD REALTY ASSOCIATES L.L.C.                       |  | DE
|TRIAD REALTY HOLDING L.L.C.                          |  | DE
|                                                     |  |   

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|U.S. UTILIPRO SOLUTIONS L.L.C.        |  | DE
|------------------------------------- |  | --
|VAUGHN PARTNERS L.L.C.                |  | NJ
|VAUGHN PRINCETON ASSOCIATES L.L.C.    |  | NJ
|WESTAGE REALTY L.L.C.                 |  | NY
|WHITE PLAINS REALTY ASSOCIATES L.L.C. |  | NY

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