 | Todd Armstrong als Jason |
 | Nancy Kovack als Medea |
 | Gary Raymond als Acastus |
 | Laurence Naismith als Argos |
 | Niall MacGinnis als Zeus |
 | Michael Gwynn als Hermes |
 | Douglas Wilmer als Pelias |
 | Jack Gwillim als King Aeetes |
 | Honor Blackman als Hera |
 | John Cairney als Hylas |
 | Patrick Troughton als Phineas |
 | Andrew Faulds als Phalerus |
 | Nigel Green als Hercules |
 | John Crawford als Polydeuces (uncredited) |
 | Ferdinando Poggi als Castor of Sparta (uncredited) |
 | Ennio Antonelli als Dmitrius, Drummer on Argo (uncredited) |
 | Harold Bradley als Guard in Palace (uncredited) |
| Aldo Cristiani als Lynceus (uncredited) |
| Eva Haddon als Medea (voice) (uncredited) |
| Doug Robinson als Eupaemus (uncredited) |
| Davina Taylor als Briseis (uncredited) |
 | Tim Turner als Jason (voice) (uncredited) |
| Jan Read | Screenplay |
| Don Chaffey | Director |
| Apollonios Rhodios | Poem |
| Maurice Rootes | Editor |
| Wilkie Cooper | Director of Photography |
| Beverley Cross | Screenplay |
| Bernard Herrmann | Original Music Composer |
| Charles H. Schneer | Producer |
| Ray Harryhausen | Visual Effects |
| Paul Maslansky | Unit Manager |
| Herbert Smith | Art Direction |
| Jack Maxsted | Art Direction |
| Bernard Herrmann | Conductor |
| Harry Gillam | Camera Operator |
| Jimmy Komisarjevsky | Unit Manager |
| Phyllis Crocker | Continuity |
| Cyril Collick | Sound Recordist |
| John Dark | Production Executive |
| James Wines | Title Designer |
| Leonardo Scavino | Unit Manager |
| Tony Sarzi-Braga | Art Direction |
| Red Law | Sound Recordist |
| Alfred Cox | Sound Editor |
| Dennis Bertera | Assistant Director |
| Ray Harryhausen | Associate Producer |
| Geoffrey Drake | Production Design |
| Eddie Powell | Stunts |
