**EXHIBIT31.2****CERTIFICATIONS**I, MarshaC. Williams, Executive Vice President and Chief Financial Officer of Equity OfficeProperties Trust, certify that:1. I have reviewed this annual report on Form 10-K of Equity Office Properties Trust; 2. Based on my knowledge, this report does not contain any untrue statement of amaterial fact or omit to state a material fact necessary to make the statementsmade, in light of the circumstances under which such statements were made, notmisleading with respect to the period covered by this report; 3. Based on my knowledge, the financial statements, and other financial informationincluded in this report, fairly present in all material respects the financialcondition, results of operations and cash flows of the registrant as of, and for,the periods presented in this report; 4. The registrant’s other certifying officer and I are responsible for establishingand maintaining disclosure controls and procedures (as defined in Exchange ActRules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (asdefined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant andhave: (a) Designed such disclosure controls and procedures, orcaused such disclosure controls and procedures to bedesigned under our supervision, to ensure that materialinformation relating to the registrant, including itsconsolidated subsidiaries, is made known to us by otherswithin those entities, particularly during the period inwhich this report is being prepared;  (b) Designed such internal control over financial reporting,or caused such internal control over financial reportingto be designed under our supervision, to providereasonable assurance regarding the reliability offinancial reporting and the preparation of financialstatements for external purposes in accordance withgenerally accepted accounting principles;  (c) Evaluated the effectiveness of the registrant’sdisclosure controls and procedures and presented in thisreport our conclusions about the effectiveness of thedisclosure controls and procedures, as of the end of theperiod covered by this report based on such evaluation;and  (d) Disclosed in this report any change in the registrant’sinternal control over financial reporting that occurredduring the registrant’s most recent fiscal quarter (theregistrant’s fourth fiscal quarter in the case of anannual report) that has materially affected, or isreasonably likely to materially affect, the registrant’sinternal control over financial reporting; and5. The registrant’s other certifying officer and I have disclosed,based on our most recent evaluation of internal control overfinancial reporting, to the registrant’s auditors and the auditcommittee of the registrant’s board of directors (or personsperforming the equivalent functions): (a) All significant deficiencies and material weaknessesin the design or operation of internal control overfinancial reporting which are reasonably likely toadversely affect the registrant’s ability to record,process, summarize and report financial information;and  (b) Any fraud, whether or not material, that involvesmanagement or other employees who have a significantrole in the registrant’s internal control overfinancial reporting.        Date: March 14, 2006 /s/ Marsha C. Williams   Marsha C. Williams   *Executive Vice President and Chief Financial Officer*