Osmosis Jones (voice)
Chris Rock
Frank
Bill Murray
Mrs. Boyd
Molly Shannon
Thrax (voice)
Laurence Fishburne
Drix (voice)
David Hyde Pierce
Bob
Chris Elliott
Shane Detomello
Elena Franklin
Leah (voice)
Brandy Norwood
Zookeeper Superintendent
Danny Murphy
Mayor Phlegmming (voice)
William Shatner
Tom Colonic (voice)
Ron Howard
Additional Character Voice (voice)
Mickie McGowan
(voice)
Sherry Lynn
Kidney Rock (voice)
Uncle Kracker
Additional Character Voices (voice)
Carlos Alazraqui
Kidney Rock
Kid Rock
Additional Character Voice (voice)
Rodger Bumpass
Additional Character Voice (voice)
Richard Steven Horvitz
Additional Character Voice (voice)
Danny Mann
Ken Olson
Police Officer
Brian Mone
Mickie T. McGowan
Hector Mercado
Zoo Visitors & Staff
Bob O'Brien
Anne Lockhart
Nurse #2
Nikki Tyler-Flynn
Paul Tuerpé
Keri Tombazian*
Steve Susskind
Robert Wisdom
Chris Phillips
Paul Pape
Emergency Room Doctor #3
Zak Penn
Marilyn Pasekoff
Herschel Sparber
Doug Stone
Al Rodrigo
Pea Soup Staff
Bo Cleary
Paul Christie
Bikini Gang
Docky
Science Fair Contestant
Laura Dunn
Oyster Boy
Willy Dunn
Zoo Visitors & Staff
Helen Britten
Emergency Room Doctor #1
Zen Gesner
Police Officer
Sean Fitzgerald
Pea Soup Manager
John-Eliot Jordan
Emergency Room Doctor #2
Marc Hyman
School Janitor
Jackie Flynn
Dreamy Photographer
Sean Gildea
Nurse #3
Elizabeth Jordan
Rif Hutton
Sally Ann Brooks
Antonio Fargas
Art Kimbro
Donald Fullilove
The Chief
Joel Silver
Janis Dardaris
Eddie Barth
Eddie Frierson
Jackie Gonneau
Jonathan Adams