Exhibit 23.1

Consent of Independent Auditors

We consent to the incorporation by reference in the Registration Statements (Form S-3 No. 333-105850 and Forms S-4 No. 333-44576 and No. 333-36053) and in the related Prospectuses of ERP Operating Limited Partnership of our report dated February 4, 2004, with respect to the consolidated financial statements and schedule of ERP Operating Limited Partnership included in this Annual Report (Form 10-K) for the year ended December 31, 2003.

	/s/ Ernst & Young LLP
	Ernst & Young LLP
Chicago, Illinois
March 12, 2004