John Wayne
Col. Cord McNally

Jorge Rivero
Capt. Pierre Cordona

Jennifer O'Neill
Shasta Delaney

Jack Elam
Phillips

Christopher Mitchum
Sgt. Tuscarora Phillips

Victor French
Ketcham

Susana Dosamantes
Maria Carmen

Sherry Lansing
Amelita

David Huddleston
Dr. Ivor Jones

Mike Henry
Rio Lobo Sheriff 'Blue Tom' Hendricks

Bill Williams
Blackthorne Sheriff Pat Cronin

Jim Davis
Riley

Dean Smith
Bide

Robert Donner
Whitey Carter

George Plimpton
George, Whitey's 4th Henchman

Edward Faulkner
Lt. Harris

Peter Jason
Lt. Ned Forsythe

Chuck Courtney
Chuck, Whitey's 2nd Henchman

Don 'Red' Barry
Feeny - Bartender (uncredited)

Sondra Currie
Blackthorne Prostitute (uncredited)

Chuck Hayward
(uncredited)

John Hudkins
Rio Lobo Deputy (uncredited)

Michael Jeffers
Barfly in Blackthorne (uncredited)

John McKee
Rio Lobo Deputy (uncredited)

Boyd 'Red' Morgan
Train Engineer (uncredited)

William H. O'Brien
Man in Army Post Saloon (uncredited)

Gregg Palmer
Pete - Henchman (uncredited)

Chuck Roberson
Corporal in Baggage Car (uncredited)

Cap Somers
Card Player (uncredited)

Bob Steele
Rio Lobo Deputy (uncredited)

Hank Worden
Hank - Hotel Clerk (uncredited)