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)