EXHIBIT 23(b)

Consent of Independent Registered Public Accounting Firm

The Board of Directors

Siebel Systems, Inc.:

We consent to the use of our reports dated March 11, 2005, relating to the consolidated balance sheets of Siebel Systems, Inc. and subsidiaries as of December 31, 2003 and 2004, and the related consolidated statements of operations and comprehensive income (loss), stockholders’ equity and cash flows for each of the years in the three-year period ended December 31, 2004, management’s assessment of the effectiveness of internal control over financial reporting as of December 31, 2004, and the effectiveness of internal control over financial reporting as of December 31, 2004, incorporated by reference in the registration statement on Form S-4 of Oracle Corporation, and to the reference to our firm under the heading “Experts” in the proxy statement/prospectus.

/s/    KPMG LLP

Mountain View, California

October 14, 2005