Arnold Schwarzenegger
Quaid
Rachel Ticotin
Melina
Sharon Stone
Lori
Michael Ironside
Richter
Marshall Bell
George / Kuato
Michael Champion
Helm
Mel Johnson Jr.
Benny
Roy Brocksmith
Dr. Edgemar
Rosemary Dunsmore
Dr. Lull
Ronny Cox
Cohaagen
Ray Baker
Mc Clane
David Knell
Ernie
Alexia Robinson
Tiffany
Dean Norris
Tony
Mark Carlton
Bartender
Debbie Lee Carrington
Thumbelina
Lycia Naff
Mary
Robert Costanzo
Harry
Michael LaGuardia
Stevens
Priscilla Allen
Fat Lady
Ken Strausbaugh
Immigration Officer
Marc Alaimo
Everett
Michael Gregory
Rebel Lieutenant
Ken Gildin
Hotel Clerk
Mickey Jones
Burly Miner
Parker Whitman
Martian Husband
Ellen Gollas
Martian Wife
Gloria Dorson
Woman in Phone Booth
Erika Carlsson
Miss Lonelyhearts
Benny Corral
Punk Cabbie
Bob Tzudiker
Doctor
Erik Cord
Lab Assistant
Frank Kopyc
Technician
Chuck Sloan
Scientist
Dave Nicolson
Scientist
Paula McClure
Newscaster
Rebecca Ruth
Reporter
Milt Tarver
Commercial Announcer
Roger Cudney
Agent
Monica Steuer
Mutant Mother
Sasha Rionda
Mutant Child
Linda Howell
Tennis Pro
Robert Picardo
Johnnycab (voice)
Anne Lockhart
Additional Voices (voice)
Kamala Lopez
Additional Voices (voice)
Morgan Lofting
Additional Voices (voice)
Patti Attar
Additional Voices (voice)
Bob Bergen
Additional Voices (voice)
Joe Unger
Additional Voices (voice)
Karlyn Michelson
Additional Voices (voice)
Allan Graf
Harry's Henchman (uncredited)
Joel Kramer
Harry's Henchman (uncredited)
Steven Lambert
Man Standing Behind Fat Lady (uncredited)
Andy Armstrong
Richter's Henchman (uncredited)
Terry Richards
Richter's Henchman (uncredited)
Bennie Moore
Richter's Subway Agent (uncredited)
Billy D. Lucas
Richter's Subway Agent (uncredited)
Graeme Crowther
Richter's Subway Agent (uncredited)
Peter Kent
Richter's Subway Agent (uncredited)
Thomas Ebert
Subway Rider (uncredited)
Frank Allen Forbes
Vestron Soldier (uncredited)