Exhibit 23.1

Consent of Registered Public Accounting Firm

We consent to the incorporation by reference in the Registration Statements (Forms S-3 No. 333-45533, No. 333-39289, No. 333-100631, No. 333-63176, No. 333-80835, No. 333-72961, No. 333-12983, No. 333-06873, No. 33-97680 and No. 33-84974; Forms S-8 No. 333-06869, No. 333-107244, No. 333-83403, No. 333-102609, No. 333-66257 and No. 333-88237; and Forms S-4 No. 333-44576 and No. 333-35873) and in the related Prospectuses of Equity Residential of our report dated February 4, 2004 (except for Notes 15, 16 and 23, as to which the date is August 17, 2004), with respect to the consolidated financial statements and schedule of Equity Residential included in this Current Report on Form 8-K.

/s/ Ernst & Young LLP

Ernst & Young LLP

Chicago, Illinois

August 17, 2004

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