After a year of marriage, a young wife sees that her husband is not the man he was before they married. He has lost all real affection for her and for his new pet dog, which she gave him as a present. Thereafter, she quickly discovers that he is not the only man in town that has changed into a completely different person. Then one evening she follows him when he goes out for a walk and discovers her husband is really an alien.
After a year of marriage, Marge Farrell (Gloria Talbott) is despondent that her husband Bill (Tom Tryon) is cold and not acting toward her the way he did before they were married. He doesn't show any signs of genuine affection towards her or toward his new dog, a surprise anniversary present from Marge. The dog barks and snarls at him whenever he approaches; he kills it in their basement, telling Marge the dog was strangled by his collar while pulling on his tethered leash. She is also becoming concerned because, wanting a family, she cannot become pregnant. After undergoing various tests, her doctor assures her she can have children; he suggests that Bill come in and see him to be tested.
She soon notices that other husbands in their social circle are acting the same way. One night, she follows Bill when he goes out for a long walk. He heads to an isolated area in the woods, where she discovers that he is not the man she thought she married but an alien impostor. An extraterrestrial life form leaves Bill's body shell and then enters a hidden spaceship.
She confronts the alien Bill, and he eventually explains that all the females on his dead planet are extinct. He and the other males of his species are taking over human men so they can have offspring with Earth's women, saving their race from extinction. Marge is horrified at the prospect and tries to warn others of the alien plot, but too many men in town have already been taken over, including the town's Chief of Police, who does nothing after hearing her story. She attempts to call Washington, D.C., but all outgoing phone lines are busy. She attempts to leave by car and the local police stop her, saying the only exit bridge is down that leads out of town.
Finally, her doctor (Ken Lynch) comes to believe her wild story, and he gathers up a posse of men he knows cannot be disguised aliens. They attack the aliens in their hidden spaceship. Bullets can't hurt the invaders, who are surrounded by some kind of force barrier. The aliens, however, prove to be defenseless against a pair of German shepherd dogs being used by the posse. The aliens are killed when the dogs attack, all except the alien Bill.
Entering the spaceship, the posse finds that all the human male captives are unconscious but still alive, including Bill. The men are each hooked up to some kind of apparatus that helps the aliens become their captives while living in faux human shells. The posse begins to disconnect the captives, which kills the aliens one-by-one. Shortly before his faux human body is destroyed, the alien Bill broadcasts a warning to his people that they've been discovered by the humans. Thereafter, a fleet of alien spaceships is seen leaving Earth space. They must seek out humanoid females elsewhere now that their breeding plan on Earth has been discovered.
Both director Gene Fowler Jr. and screenwriter Louis Vittes had worked in series television and had some success. With I Married a Monster from Outer Space, both had some creative freedom, although Vittes was notoriously resistant to any changes to his script, to the annoyance of the leads. Principal photography for I Married a Monster from Outer Space began on April 21 and ended in early May 1958. On September 10, 1958, the film premiered in Los Angeles, followed by its U. S. and Canadian theatrical release in October.
Upon its release, I Married a Monster from Outer Space proved to be a hit with audiences and critics. Despite its modest budget and unpretentious production values, the film was an ideal filler for the drive-in crowd. Originally slated as the A film in a double feature with The Blob (1958), I Married a Monster from Outer Space was relegated to the bottom of the playbill because audiences preferred the intriguing full color monster feature over this monochromatic, more sombre, domestic invasion entry.
Due to its exploitative and sensationalized title, I Married a Monster from Outer Space has long been ignored by critics and film historians, although it received respectable reviews, both in contemporary and in later reviews. Danny Peary described it as "an intelligent, atmospheric, subtly made sci-fi thriller", Tom Milne of Time Out magazine found "good performances, strikingly moody camerawork, a genuinely exciting climax", and Leonard Maltin called it a "pretty good little rehash of Invasion of the Body Snatchers" with "some nice, creepy moments".
2002: AFI's 100 Years...100 Passions – Nominated
The film is recognized by American Film Institute in these lists:
The Aurum Film Encyclopedia concluded that "while the film was clearly fueled by the Cold War mentality of the fifties, in retrospect it is its sexual politics that are more interesting, and disturbing". The hint at a subtext of "sexual angst" by Tom Milne is emphasized by German critic Georg Seeßlen, linking I Married a Monster from Outer Space and Attack of the 50 Foot Woman (1958) to Film noir: Their subjects in common, states Seeßlen, are the distrust between the sexes and the depiction of marriage as a trap where the death of one partner seems inevitable.
In 1998 the now defunct UPN television network produced and aired a remake of the film titled I Married a Monster, with Richard Burgi as the alien husband.
In 2004 Paramount released a DVD of the film which, other than the open matte, full frame (1.33:1) format of the 1998 VHS release, cropped the original 1:85:1 image to the modern 16:9 (1.78:1) TV aspect ratio.
The label L'Atelier 13 released a Spanish language DVD under the title Me casé con un monstruo del espacio exterior.