Exhibit 23.1
Consent
of Independent Registered Public Accounting Firm
We consent to the incorporation by reference in Registration
Statement
No. 333-157952
on
Form S-3
and Registration Statement Nos.
333-123263,
333-113550,
333-88024,
333-88020,
333-59630,
333-59632,
333-33728,
333-73027,
333-93900,
333-2594,
333-146794,
and
333-169293
on
Form S-8
of our reports dated February 18, 2011, relating to the
consolidated financial statements of ACI Worldwide, Inc. and
subsidiaries (“ACI Worldwide, Inc.”) as of and for the
years ended December 31, 2010 and 2009, and the
effectiveness of ACI Worldwide Inc.’s internal control over
financial reporting as of December 31, 2010, appearing in
this Annual Report on
Form 10-K
of ACI Worldwide, Inc. for the year ended December 31, 2010.
/s/ DELOITTE &
TOUCHE LLP
Omaha, Nebraska
February 18, 2011