John Wayne
Role: Col. Cord McNally
Jorge Rivero
Role: Capt. Pierre Cordona
Jennifer O'Neill
Role: Shasta Delaney
Christopher Mitchum
Role: Sgt. Tuscarora Phillips
Victor French
Role: Ketcham
Susana Dosamantes
Role: Maria Carmen
Sherry Lansing
Role: Amelita
David Huddleston
Role: Dr. Ivor Jones
Mike Henry
Role: Rio Lobo Sheriff 'Blue Tom' Hendricks
Bill Williams
Role: Blackthorne Sheriff Pat Cronin
Robert Donner
Role: Whitey Carter
George Plimpton
Role: George, Whitey's 4th Henchman
Edward Faulkner
Role: Lt. Harris
Peter Jason
Role: Lt. Ned Forsythe
Chuck Courtney
Role: Chuck, Whitey's 2nd Henchman
Robert Rothwell
Role: Whitey's 3rd Henchman
Don 'Red' Barry
Role: Feeny - Bartender (uncredited)
Sondra Currie
Role: Blackthorne Prostitute (uncredited)
Chuck Hayward
Role: (uncredited)
Conrad Hool
Role: Bart (uncredited)
Lance Hool
Role: Picket (uncredited)
John Hudkins
Role: Rio Lobo Deputy (uncredited)
Michael Jeffers
Role: Barfly in Blackthorne (uncredited)
Frank Kennedy
Role: Minor Role (uncredited)
Richard LaMarr
Role: Man in Army Post Saloon (uncredited)
John McKee
Role: Rio Lobo Deputy (uncredited)
Boyd 'Red' Morgan
Role: Train Engineer (uncredited)
William H. O'Brien
Role: Man in Army Post Saloon (uncredited)
Gregg Palmer
Role: Pete - Henchman (uncredited)
Jim Prejean
Role: Union Soldier (uncredited)
Rudy Robbins
Role: Man (uncredited)
Chuck Roberson
Role: Corporal in Baggage Car (uncredited)
Danny Sands
Role: Man Delivering Message to Jail (uncredited)
Cap Somers
Role: Card Player (uncredited)
Bob Steele
Role: Rio Lobo Deputy (uncredited)
Tommy Tedesco
Role: Guitar Player in Opening Credits (uncredited)
Ethan Wayne
Role: Boy (uncredited)
Hank Worden
Role: Hank - Hotel Clerk (uncredited)