**Exhibit 23.1**CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRMWe consent to the incorporation by reference in the Registration Statements and relatedProspectuses of Equity Office Properties Trust for the registration of: **•** guarantee of $3.0 billion of debt securities and warrants exercisable for debtsecurities (registration statement no. 333-116202-01);  **•** 25,000,000 common shares of beneficial interest issuable under the Equity OfficeProperties Trust Dividend Reinvestment and Share Purchase Plan (registrationstatement no. 333-81303);  **•** 328,691 common shares of beneficial interest (registration statement no. 333-72922);  **•** 16,784,214 common shares of beneficial interest (registration statement no.333-57526);  **•** guarantee of $4.0 billion of debt securities and warrants exercisable for debtsecurities (registration statement no. 333-58976);  **•** 12,398,803 common shares of beneficial interest (registration statement no.333-35590);  **•** 1,012,623 common shares of beneficial interest (registration statement no. 333-88481);  **•** 21,649,274 common shares of beneficial interest (registration statement no.333-86079);  **•** 137,427 common shares of beneficial interest (registration statement no. 333-69619);  **•** 6,854,451 common shares of beneficial interest (registration statement no. 333-62213);  **•** 8,205,059 common shares of beneficial shares of beneficial interest (registrationstatement no. 333-40401-01);  **•** 20,210,129 common shares of beneficial interest (registration statement no.333-59069);  **•** 6,000,000 5.25% Series B convertible, cumulative preferred shares of beneficialinterest and 8,403,360 common shares of beneficial interest issuable upon conversionof the 5.25% Series B convertible, cumulative preferred shares of beneficial interest(registration statement no. 333-61105);  **•** $1.5 billion of common shares of beneficial interest, preferred shares of beneficialinterest, common share warrants and preferred share warrants (registration statementno. 333-58729);  **•** 1,628,009 common shares of beneficial interest (registration statement no. 333-58687);
 

 
 **•** the Registration Statements relating to 3,124,774 common shares of beneficialinterest issuable under Stock Option Agreements under the Spieker Properties, Inc1993 Stock Incentive Plan and Directors’ Stock Option Plan (registration statementno. 333-64604);  **•** 3,681,212 common shares of beneficial interest issuable under the 1995 and 1997 stockoption agreements, stock option agreements under the Cornerstone 1998 long-termincentive plan and Cornerstone director stock option agreements (registrationstatement no. 333-39920);  **•** 8,449,434 common shares of beneficial interest issuable under the Amended andRestated 1997 Share Option and Share Award Plan (registration statement no.333-72205);  **•** 2,000,000 common shares of beneficial interest issuable under the Equity OfficeProperties Trust 1997 Non-Qualified Employee Share Purchase Plan (registrationstatement no. 333-72187);  **•** 4,749,095 common shares of beneficial interest issuable under the Beacon PropertiesCorporation 1994 Stock Option and Incentive Plan and 1996 Stock Option Plan(registration statement no. 333-42393);  **•** 2,000,000 common shares of beneficial interest issuable under the Equity OfficeProperties Trust 1997 Non-Qualified Employee Share Purchase Plan (registrationstatement no. 333-33503);  **•** 11,121,786 common shares of beneficial interest issuable under the Amended andRestated 1997 Share Option and Share Award Plan (registration statement no.333-33501); and  **•** 20,000,000 common shares of beneficial interest issuableunder the Equity Office Properties Trust 2003 Share Option Incentive Plan(registration statement no. 333-106096).of ourreport dated March 8, 2006 with respect to the consolidated financial statements andschedule of Equity Office Properties Trust, Equity Office Properties Trust’s management’sassessment of the effectiveness of internal control over financial reporting, and the effectivenessof internal control over financial reporting of Equity Office Properties Trust, included in thisAnnual Report (Form 10-K) for the year ended December 31, 2005.         /s/  ERNST & YOUNG LLP Chicago, Illinois