• 
  Peter Farrelly

  regizor
• 
  Bobby Farrelly

  regizor

• 
  Marc Hyman

  scenarist

• 
  Chris Rock

  Osmosis Jones (voce)
• 
  Laurence Fishburne

  Thrax (voce)
• 
  David Hyde Pierce

  Drix (voce)
• 
  Bill Murray

  Frank Detorre
• 
  Jason Krause

  Kidney Rock

• 
  Jackie Gonneau

  voci adiţionale
• 
  Janis Dardaris

  voci adiţionale
• 
  Molly Shannon

  Doamna Boyd
• 
  Kid Rock

  Kidney Rock
• 
  Paul Christie

  voci adiţionale
• 
  Uncle Kracker

  Kidney Rock
• 
  Sally Ann Brooks

  voci adiţionale

• 
  Michael Carven

  voci adiţionale
• 
  Jimmie Bones

  Kidney Rock
• 
  Ron Howard

  Tom Colonic (voce)
• 
  Joe C.

  Kidney Rock
• 
  Keith Anthony

  voci adiţionale
• 
  Chris Elliott

  Bob
• 
  William Shatner

  Primarul Phlegmming (voce)
• 
  Elena Franklin

  Shane
• 
  Shannon Gregory

  voci adiţionale
• 
  Wendy Dillon

  voci adiţionale
• 
  Brandy Norwood

  Leah
• 
  Rif Hutton

  voci adiţionale
• 
  Carlos Alazraqui

  voci adiţionale
• 
  Donald Fullilove

  voci adiţionale
• 
  Rodger Bumpass

  voci adiţionale
• 
  Eddie Frierson

  voci adiţionale
• 
  Richard Steven Horvitz

  voci adiţionale
• 
  Antonio Fargas

  voci adiţionale
• 
  Jonathan Adams

  voci adiţionale
• 
  Eddie Barth

  voci adiţionale
• 
  Kenny Olson

  Kidney Rock
• 
  Stefanie Eulinberg

  Kidney Rock
• 
  Joel Silver

  Police Chief
• 
  Steve Susskind

  Additional Character Voice
• 
  Paul Pape

  Additional Character Voice
• 
  Sydney J. Bartholomew Jr.

  The Zoo Visitors & Staff
• 
  Zak Penn

  Emergency Room Doctor #3
• 
  Ben Stein

  Doc
• 
  Jackie Flynn

  School Janitor
• 
  Mickie McGowan

  Additional Character Voice
• 
  Paul Tuerpe

  Additional Character Voice
• 
  Marc Hyman

  Emergency Room Doctor #2
• 
  Bill Beauchene

  The Science Fair Contestants & Families
• 
  Danny Murphy

  Zookeeper Superintendent
• 
  Zen Gesner

  Emergency Room Doctor #1
• 
  Kathryn Frick

  Nurse #1
• 
  Sean Gildea

  Dreamy Photographer
• 
  Danny Mann

  Additional Character Voice
• 
  Robert Wisdom

  Additional Character Voice
• 
  Jonathan Adams

  Additional Character Voice (voice)

• 
  Bobby Farrelly

  producător
• 
  Dennis Edwards

  producător
• 
  Peter Farrelly

  producător
• 
  Bradley Thomas

  producător
• 
  Zak Penn

  producător
• 
  Aaron Parry

  producător asociat
• 
  John Walker

  producător asociat
• 
  Mark Irwin

  imagine
• 
  Marc S. Fischer

  co-producer
• 
  Pamela Withers

  costume
• 
  Sam Seig

  montaj
• 
  Lois Freeman-Fox

  montaj
• 
  Stephen Schaffer

  montaj
• 
  Money Mark

  coloană sonoră
• 
  Randy Edelman

  coloană sonoră
• 
  Sydney J. Bartholomew Jr.

  design de producţie
• 
  Scott Jacobson

  decoruri