Trailer
Images
 | Jimmy Hunt as David Maclean |
 | Arthur Franz as Dr. Stuart Kelston |
 | Helena Carter as Dr. Pat Blake, MD |
 | Leif Erickson as Mr. George MacLean |
 | Hillary Brooke as Mrs. Mary MacLean |
 | Morris Ankrum as Col. Fielding |
 | Walter Sande as Police Sgt. Mack Finlay |
 | Bert Freed as Police Chief A.C. Barrows |
 | Max Wagner as Army Sgt. Rinaldi |
 | Charles Gibb as Lt. Blair |
 | Milburn Stone as Army Capt. Roth |
 | Douglas Kennedy as Officer Jackson |
 | Charles Cane as Officer Blaine |
 | Fay Baker as Mrs. Wilson |
| Janine Perreau as Kathy Wilson |
 | John Eldredge as Mr. Turner |
 | Barbara Billingsley as Kelston's Secretary |
 | Richard Deacon as MP |
| Gil Herman as Major Clary |
| Luce Potter as The Martian Intelligence |
| Lock Martin as Mutant Carrying David to 'Intelligence' |
| Max Palmer as Second Mutant Guarding the "Intelligence" |
| Todd Karns as Jim the Gas Station Attendant |
 | Frank Wilcox as Pentagon Chief of Staff |
 | Robert Shayne as Dr. William Wilson |
 | William Phipps as Sgt. Baker |
 | William Forrest as Col. Mayberry |
 | Peter Brocco as Brainard (bit) |
| Directing | |
| William Cameron Menzies | Director |
Sound | |
| Raoul Kraushaar | Original Music Composer |
Camera | |
| John F. Seitz | Director of Photography |
Editing | |
| Arthur Roberts | Editor |
Art | |
| Boris Leven | Art Direction |
Production | |
| Edward L. Alperson | Producer |
| Edward L. Alperson Jr. | Associate Producer |
Writing | |
| Richard Blake | Screenplay |
| John Tucker Battle | Story |
Costume & Make-Up | |
| Gene Hibbs | Makeup Artist |
| Ruby Felker | Hairstylist |
Visual Effects | |
| Jack Cosgrove | Visual Effects |
