Phil LaMarr

Osmosis Jones (voice)

Jeff Bennett

Drix (voice)

Alanna Ubach

Mayor Paul Spryman / Hector's Mom (voice)

Justin Cowden

Hector Cruz (voice)

Tasia Valenza

Maria Amino (voice)

Jim Cummings

Police Chief Gluteus (voice)

Jim Belushi

Captain Quinine (voice)

Cree Summer

Mayor Santorini (voice)

Kath Soucie

Naurine / Celly Katz (voice)

Andrea Martin

Aunti Histamine (voice)

Candi Milo

Mumsy Glop (voice)

Miriam Flynn

Drixeen (voice)

Neil Ross

Cop (voice)

Justine Bateman

Rota (voice)

Billy West

Muscle Cell (voice)

Danny Bonaduce

Smirch (voice)

Tim Curry

Scarlet Fever (voice) · Nick O'Teen (voice)

April Winchell

Cafeteria Lady (voice)

Tara Strong

Ashley / Carbon Monoxide (voice) · Jenna (voice)

Wendie Malick

Number 2 / Sticky Flagella (voice)

Jess Harnell

Shwee (voice)

Julian Sands

Penicillin G (voice)

Pat Fraley

Brain Advisor #1 (voice)

Rino Romano

Jude (voice)

Danny Mann

Rudy (voice)

Frank Welker

Dander (voice) · Tar (voice)

Roger Rose

Jumbo (voice)

Brad Garrett

Strepfinger (voice)

Charlie Adler

Abglobtus Goop (voice)

Henry Winkler

Sal Monella (voice)

Brian Posehn

Sylvian Fisher (voice)

Kathy Najimy

Loretta Epstein (voice)

Jeffrey Tambor

The Mole (voice)

Vivica A. Fox

Ellen Patella (voice)

Dawnn Lewis

Cilia Tyson (voice)

Joe Lala

Hector's Dad (voice)

Danny Cooksey

Shane (voice)

Hope Levy

Brittany Estrogen (voice)

Jeffrey Garcia

Ricardo Amino (voice)

Dee Bradley Baker

Father Glop (voice)

Kimberly Brooks

Christine Kolchuck (voice)

Rob Paulsen

Stickety Lipid (voice)

Kevin Michael Richardson

Rescue Cell (voice)

Susan Silo

Cryo (voice)