 | Michael Keith als Eric Carter |
 | Harry Holcombe als Dr. Arnold Johnson |
 | James Yagi als Yutaka Omura |
 | Tadao Takashima als Osamu Sakurai |
 | Kenji Sahara als Kazuo Fujita |
 | Ichirō Arishima als Mr. Tako |
 | Byron Morrow als Newscaster |
 | Les Tremayne als Commander Roberts / General Masami Shinzo / Narrator (voice) |
 | George Takei als Osamu Sakurai (voice) |
 | Mie Hama als Fumiko Sakurai (uncredited) |
 | Akiko Wakabayashi als Tamiye (uncredited) |
 | Akemi Negishi als Chikiro's Mother (Dancing Girl) (uncredited) |
 | Akihiko Hirata als Dr. Shigezawa (uncredited) |
| Bruce Mason als Misc. characters (voice) |
 | Paul Howard als Misc. characters (voice) |
 | Yū Fujiki als Kinsaburo Furue |
 | Jun Tazaki als General Masami Shinzo (uncredited) |
 | Yoshio Kosugi als Farou Island Chief (uncredited) |
 | Ikio Sawamura als Witch Doctor (uncredited) |
 | Kenzō Tabu als Dreary Newscaster (uncredited) |
 | Victor Millan als Rodrigo Infante (uncredited) |
 | Haruo Nakajima als Godzilla |
 | Shōichi Hirose als King Kong |
| Paul Mason | Writer |
| Bruce Howard | Writer |
| John Beck | Producer |
| Thomas Montgomery | Director |
| Heinz Roemheld | Music |
| Paul Sawtell | Music |
| Hans J. Salter | Music |
| Willis H. O'Brien | Original Concept |
| Ishirō Honda | Director |
| Peter Zinner | Music Supervisor |
| William L. Stevenson | Sound Effects |
| Shinichi Sekizawa | Screenplay |
| Eiji Tsuburaya | Special Effects |
| George Worthing Yates | Original Story |
| Peter Zinner | Supervising Editor |
| Hajime Koizumi | Director of Photography |
| Toshio Takashima | Lighting Technician |
| Eiji Tsuburaya | Visual Effects |
| Kenji Aoki | Choreographer |
| Sadamasa Arikawa | Special Effects |
| Hiroshi Mukoyama | Visual Effects |
| Tomoyuki Tanaka | Producer |
| Takeo Kita | Production Design |
| Teruaki Abe | Production Design |
