Sal Ponti as Demetrios

Joyce Taylor as Princess Antillia

John Dall as Zaren

William Smith as Captain of the Guard

Edward Platt as Azor the High Priest

Frank De Kova as Sonoy the Astrologer

Berry Kroeger as Surgeon

Edgar Stehli as King Kronas

Wolfe Barzell as Petros, Demetrios' Father

Jay Novello as Xandros the Greek Slave

Paul Frees as Narrator / Multiple Voices (voice)

Nestor Paiva as Megalos (uncredited)

John Hart as Nobleman (uncredited)

Phyllis Douglas as Girl (uncredited)

I. Stanford Jolley as Governor of Rivers (uncredited)

Gene Roth as Governor of Animals (uncredited)

Charles Horvath as Nobleman (uncredited)

Charles Cirillo as Slave (uncredited)

George Bruggeman as Guard (uncredited)

Robert 'Big Buck' Maffei as Andex the Giant (uncredited)

Byron Morrow as Governor of the Mountains (uncredited)

Will J. White as Officer (uncredited)

Ralph Smiley as Pavlo (uncredited)

Harry Fleer as Governor of Science (uncredited)

David Dyer as Priest (uncredited)

Alan Callow as Norseman Slave (uncredited)