Exhibit 23.1 INDEPENDENT AUDITOR'S CONSENT We consent to the incorporation by reference in this Registration Statement of Fiserv, Inc. on the Post-Effective Amendment No. 1 to Form S-4 on Form S-3 of our report dated October 16, 1997, appearing in the Current Report on Form 8-K dated October 22, 1997. We also consent to the reference to us under the heading"Experts" in the Prospectus, which is part of this Registration Statement. /s/ DELOITTE & TOUCHE LLP DELOITTE & TOUCHE LLP Milwaukee, Wisconsin December 31, 1997