Buster Crabbe as Flash Gordon
Carol Hughes as Dale Arden
Frank Shannon as Dr. Alexis Zarkov
Charles B. Middleton as Ming the Merciless.

Roland Drew as Prince Barin
Shirley Deane as Princess Aura
Donald Curtis as Captain Ronal (uncredited)
Lee Powell as Radio Officer Roka
Don Rowan as Captain Torch
Victor Zimmerman as Lieutenant Thong
Anne Gwynne as Lady Sonja
John Hamilton as Professor Gordon
Edgar Edwards as Captain Turan
William Royle as Captain Sudan
Sigurd Nilssen as Count Korro
Luli Deste as Queen Fria (uncredited)
Michael Mark as Professor Karm
Byron Foulger as Professor Druk
As-yet unidentified player as Radio Officer Tekla
Ray Mala as Prince of the Rock People (uncredited)
Buster Crabbe as Flash Gordon
Carol Hughes as Dale Arden
Frank Shannon as Dr. Alexis Zarkov
Charles B. Middleton as Ming the Merciless.
Roland Drew as Prince Barin
Shirley Deane as Princess Aura
Donald Curtis as Captain Ronal (uncredited)
Lee Powell as Radio Officer Roka
Don Rowan as Captain Torch
Victor Zimmerman as Lieutenant Thong
Anne Gwynne as Lady Sonja
John Hamilton as Professor Gordon
Edgar Edwards as Captain Turan
William Royle as Captain Sudan
Sigurd Nilssen as Count Korro
Luli Deste as Queen Fria (uncredited)
Michael Mark as Professor Karm
Byron Foulger as Professor Druk
As-yet unidentified player as Radio Officer Tekla
Ray Mala as Prince of the Rock People (uncredited)
Flash Gordon Conquers the Universe