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)