James Marsden

as Diggs (voice)

Nick Nolte

as Butch (voice)

Christina Applegate

as Catherine (voice)

Bette Midler

as Kitty Galore (voice)

Pascale Hutton

as Jackie

Katt Williams

as Seamus (voice)

Neil Patrick Harris

as Lou (voice)

Sean Hayes

as Mr. Tinkles (voice)

Wallace Shawn

as Calico (voice)

Roger Moore

as Tab Lazenby (voice)

Joe Pantoliano

as Peek (voice)

Michael Clarke Duncan

as Sam (voice)

Chris O'Donnell

as Shane

Jack McBrayer

as Chuck

Fred Armisen

as Freidrich

Kiernan Shipka

as Little Girl

Paul Rodríguez

as Crazy Carlito (voice)

J.K. Simmons

as Gruff K-9 (voice)

E. G. Daily

as Scrumptious / Patches / Catherine's Niece (voice)

Phil LaMarr

as Paws / Cat Spy Analyst (voice)

Michael Beattie

as Angus MacDougall (voice)

Jeff Bennett

as Duncan MacDougall (voice)

Malcolm Stewart

as Captain Flemming

Dawn Chubai

as Reporter

Keith Dallas

as Coit Tower Guard

Len Morganti

as Rex (voice)

Betty Phillips

as Cat Lady

Christopher Lee Parson

as Hep Cat / Cat Spy Analyst (voice)

Bumper Robinson

as Cool Cat / Dog Killa / Cat Spy Analyst / Slim (voice)

Rick D. Wasserman

as Rocky (voice)

Roger L. Jackson

as Inmate Fat Cat (voice)

Bonnie Cahoon

as Dog HQ PA / Catherine's Niece (voice)

André Sogliuzzo

as Snobby K-9 (voice)

Carlos Alazraqui

as Cat Gunner / Cat Spy Analyst (voice)

Grey DeLisle

as Security Bulldog / Catherine's Niece / Cat Spy Analyst (voice)

Ingrid Tesch

as Mom

Amitai Marmorstein

as Playland Worker

Robert Hewko

as Old Man

Mark Burgess

as Used Car Salesman

Sage Brocklebank

as Park Patron