Todd Armstrong as Jason

Nancy Kovack as Medea

Gary Raymond as Acastus

Laurence Naismith as Argos

Niall MacGinnis as Zeus

Michael Gwynn as Hermes

Douglas Wilmer as Pelias

Jack Gwillim as King Aeetes

Honor Blackman as Hera

John Cairney as Hylas

Patrick Troughton as Phineas

Andrew Faulds as Phalerus

Nigel Green as Hercules

John Crawford as Polydeuces (uncredited)

Ferdinando Poggi as Castor of Sparta (uncredited)

Ennio Antonelli as Dmitrius, Drummer on Argo (uncredited)

Harold Bradley as Guard in Palace (uncredited)

Aldo Cristiani as Lynceus (uncredited)

Eva Haddon as Medea (voice) (uncredited)

Doug Robinson as Eupaemus (uncredited)

Davina Taylor as Briseis (uncredited)

Tim Turner as Jason (voice) (uncredited)