It was filmed in Rome, Italy, with some location shots taken at Esposizione Universale Roma. It was released theatrically in the United States by American International Pictures and the UK in 1966. In the 1980s, the film fell into the public domain. MGM Home Video, the current owners of the AIP film catalog, released a digitally remastered widescreen print on DVD in September 2005.
In the year 1968, every day is the same for Dr. Robert Morgan (Price): he wakes up, gathers his weapons, and then goes hunting for vampires. Morgan lives in a world where everyone else has been infected by a plague that has turned them into undead, vampiric creatures that cannot stand sunlight, fear mirrors, and are repelled by garlic. They would kill Morgan if they could, but fortunately, they are weak and unintelligent. At night, Morgan locks himself inside his house; during the day, he kills as many vampires as he can, burning the bodies.
A flashback sequence explains that, three years before, Morgan's wife and daughter had succumbed to the plague, before it was widely known by the public that the dead would return to life. Instead of taking his wife to the same public burn pit used to dispose of his daughter's corpse, Morgan buried her without the knowledge of the authorities. When his wife returned to his home and attacked him, Morgan became aware of the need to kill the plague victims with a wooden stake. Morgan hypothesizes that he is immune to the bacteria because he was bitten by an infected vampire bat when he was stationed in Panama, which introduced a diluted form of the plague into his blood.
One day, a dog appears in the neighborhood. Desperate for companionship, Morgan chases after the dog, but does not catch it. Some time later, the dog appears, wounded, at Morgan's doorstep. He takes the dog into his home and treats its wounds, looking forward to having company for the first time in three years. He quickly discovers, however, that it, too, has become infected with the plague. Morgan is later seen burying the dog, which he has impaled with a wooden stake.
After burying the dog, Morgan spots a woman in the distance. The woman, Ruth, is terrified of Morgan at first sight, and runs from him. Morgan convinces her to return to his home, but is suspicious of her true nature. Ruth becomes ill when Morgan waves garlic in her face, but claims that she has a weak stomach.
Morgan's suspicion that Ruth is infected is confirmed when he discovers her attempting to inject herself with a combination of blood and vaccine that holds the disease at bay. Ruth initially draws a gun on Morgan, but surrenders it to him. Ruth then tells him that she is part of a group of people like her — infected but under treatment — and was sent to spy on Morgan. The vaccine allows the people to function normally with the drug in the bloodstream, but once it wears off, the infection takes over the body again. Ruth explains that her people are planning to rebuild society as they destroy the remaining vampires, and that many of the vampires Morgan killed were technically still alive. Ruth desperately urges Morgan to flee, but he inexplicably refuses.
While Ruth is asleep, Morgan transfuses his own blood into her. She is immediately cured, and Morgan sees hope that, together, they can cure the rest of her people. Moments later, however, Ruth's people attack. Morgan takes the gun and flees his home while the attackers kill the vampires gathered around Morgan's home.
Ruth's people spot Morgan and chase him. He exchanges gunfire with them, and picks up tear gas grenades from a police station armory along the way. While the tear gas delays his pursuers somewhat, Morgan is wounded by gunfire and retreats into a church. Despite Ruth's protests to let Morgan live, his pursuers finally impale him on the altar with a spear. With his dying breaths, Morgan denounces his pursuers as "freaks", and declares that he is the last true man on earth.Vincent Price as Dr. Robert Morgan (in others as Robert Neville)
Franca Bettoia as Ruth Collins
Emma Danieli as Virginia Morgan
Giacomo Rossi-Stuart as Ben Cortman
Umberto Raho as Dr. Mercer
Christi Courtland as Kathy Morgan
Antonio Corevi as the Governor
Ettore Ribotta as the TV Reporter
Rolando De Rossi
Carolyn De Fonseca dubbed for Franca Bettoia's voice in the English release of the film. She was uncredited.
Giuseppe Mattei, as the leader of the survivors, was also uncredited.
Producer Anthony Hinds purchased the rights to Matheson's novel for Hammer Productions. Matheson wrote a script, but the British censors would not allow its production, so Hinds sold the script to Robert Lippert. Lippert originally told Matheson that Fritz Lang was to direct, but eventually Sidney Salkow was chosen. To save money, the film was shot in Italy with a predominantly Italian cast and crew.
The films is different to the novel on which it is based. The protagonist of the novel is named Robert Neville, not Robert Morgan. The movie also changed the protagonist's profession from plant worker to scientist. The film's vampires are almost zombie-like, whereas in the book, they are fast, capable of running and climbing. The dog that shows up on Neville's doorstep is timid in the novel, and comes and goes as it pleases. The relationship with Ruth also slightly differs from the novel, and no transfusion takes place; a cure seems implausible, even as Neville hopes he will find one. Ruth escapes after Neville discovers that she is infected. He is not captured until many months later, and even then he barely fights. The book ends shortly before Neville is to be executed. Ruth returns to give him suicide pills, and finds it ironic that he has become as much of a legend to the new society as vampires once were to his (hence the title). The novel implies that the vampire plague resulted from a biological disease. The origin of the disease is not explained in The Last Man on Earth, and is altered in the subsequent adaptations.
Although the film was not considered a success upon its release, the film later gained a more favorable reputation as a classic of the genre. As of November 2011, The Last Man on Earth holds a 71% rating on Rotten Tomatoes. Phil Hall of Film Threat called The Last Man on Earth "the best Vincent Price movie ever made." Awarding the film three and a half stars out of four, Danél Griffin of Film as Art said, "Directors Sidney Salkow and Ubaldo Ragona and star Vincent Price (giving a poignant, straightforward performance) are able to conjure up some genuine chills here, mainly in the use of stark, black-and-white images and the underlining mood of the piece."
Among the less favorable reviews, Steve Biodrowski of Cinefantastique felt the film was "hampered by an obviously low budget and some poorly recorded post-production dubbing that creates an amateurish feel, undermining the power of its story", while Jonathan Rosenbaum of the Chicago Reader remarked, "Some would consider this version better than the 1971 remake with Charlton Heston, The Omega Man, but that isn't much of an achievement."
Among the film's creators, Price "had a certain fondness for the film" and felt it was better than the 1971 The Omega Man. Richard Matheson co-wrote the film's screenplay, but was unhappy with the results. To keep receiving residual income from the film, though, he had to be credited, so he used the name "Logan Swanson" - a combination of his wife's mother's maiden name and his mother's maiden name. Matheson said: "I was disappointed in the film, even though they more or less followed my story. I think Vincent Price, whom I love in every one of his pictures that I wrote, was miscast. I also felt the direction was kind of poor. I just didn’t care for it."