Anthony Hopkins as Dr. Ethan Powell

Cuba Gooding Jr. as Dr. Theo Caulder

Donald Sutherland as Ben Hillard

Maura Tierney as Lynn Powell

George Dzundza as Dr. John Murray

John Ashton as Guard Dacks

John Aylward as Warden Keefer

Doug Spinuzza as Nicko

Thomas Q. Morris as Pete

Vivienne Sendaydiego as Catherine

Paul Bates as Bluto

Rex Linn as Gurad Alan

Rod McLachlan as Guard Anderson

Tracey Ellis as Annie

Kim Ingram as Lester Rodman

Paul Collins as Tom Hanley

Marc Macaulay as Foley

Jim Grimshaw as Boaz

Louanne Stephens as Marjorie Powell

Ajgie Kirkland as Captain Kagona

Chike Kani Omo as David

Ivonne Coll as Dr. Marzuez

Pat McNamara as Dr. Josephson

Roger Floyd as Gilbert

Kurt Smildsin as Guard #1

Jim R. Coleman as Guard #2

Gary Bristow as Federal Marshall

David Deever as Man in Car

Tim Goodwin as Helmet Man

Kevin-Michael Moore as Prisoners

Alex Kalognomos as Prisoners

Jimmy Dipisa as Prisoners

Manwell Hendrix as Prisoners

Kevin McNally as Prisoners

Joe Tacke as Prisoners

Bertram Wallace as Prisoners

John Travis as Bartender Mike

Dave Anthony as Gorilla Performers

John Munro Cameron as Gorilla Performers

Jay Caputo as Gorilla Performers

Garon Michael as Gorilla Performers

Misty Rosas as Gorilla Performers

David St. Pierre as Gorilla Performers

Verne Troyer as Gorilla Performers

Tory Kittles as Prisoner (uncredited)

Tyrone C. Wiggins as Soldier (uncredited)

Rico Paisley as Uniform Cop (uncredited)

Linda Harmon as Singer (uncredited)

Darren T. Knaus as Gorilla Vocals (uncredited)