Chris Rock

Osmosis Jones (voice)

Laurence Fishburne

Thrax (voice)

David Hyde Pierce

Drix (voice)

Brandy Norwood

Leah (voice)

Bill Murray

Frank Detorre

Molly Shannon

Mrs. Boyd

William Shatner

Mayor Phlegmming (voice)

Ron Howard

Tom Colonic (voice)

Sherry Lynn

(voice)

Mickie McGowan

Additional Character Voice (voice)

Chris Elliott

Bob

Elena Franklin

Shane Detorre

Kid Rock

Kidney Rock

Uncle Kracker

Kidney Rock (voice)

Carlos Alazraqui

Additional Character Voices (voice)

Rodger Bumpass

Additional Character Voices (voice)

Richard Steven Horvitz

Additional Character Voices (voice)

Danny Mann

Additional Character Voices (voice)

Mickie McGowan

Additional Character Voices (voice)

Jonathan Adams

Additional Character Voices (voice)