Igor

John Cusack

as Igor (voice)

Myleene Klass

as Dr. Holzwurm (voice)

Robin Walsh

as Dr. Holzwurm's Igor (voice)

Matt McKenna

as Dr. Herzschlag (voice)

John Cleese

as Dr. Glickenstein (voice)

Steve Buscemi

as Scamper (voice)

Sean Hayes

as Brain (voice)

Eddie Izzard

as Dr. Schadenfreude (voice)

Jay Leno

as King Malbert (voice)

Jennifer Coolidge

as Jaclyn / Heidi (voice)

Molly Shannon

as Eva (voice)

James Lipton

as Himself

Christian Slater

as Dr. Schadenfreude's Igor (voice)

Arsenio Hall

as Carl Cristall (voice)

Jess Harnell

as Announcer / Royal Guard #2 (voice)

Zoë Bright

as Blind Woman / Killiseum Fan #1 (voice)

Sophia Eraklis

as Blind Orphan #1 (voice)

A. Cheron Hall

as Blind Orphan #2 / Blind Orphan #4 (voice)

Alexander Leondis

as Blind Orphan #3 (voice)

Michael Leondis

as Blind Orphan #6 (voice)

Nicole Leondis

as Blind Orphan #7 (voice)

Juliana Leondis

as Blind Orphan #5 (voice)

Robin Tisserand

as Blind Orphan #8 (voice)

Paul Vogt

as Buzz Offmann (voice)

Frank Welker

as Animals' vocal effects (voice) (uncredited)