As a follow-up to my last post, here's The Last Man on Earth (1964) starring Vincent Price. Although the antagonists here are vampires this film is the direct inspiration for today's "zombie apocalypse" movies.
From The Encyclopedia of Science Fiction:
L'ultimo uomo della terra
Film (1964; vt The Last Man on Earth). La Regina/Alta Vista. Directed by Sidney Salkow, Ubaldo Ragona, starring Vincent Price, Franca Bettoia. Screenplay Logan Swanson (pseudonym of Richard Matheson, who disliked the rewrite), William P Leicester, based on Matheson's I Am Legend (1954). 86 minutes. Black and white.
This Italian/US coproduction was the first film version of Matheson's novel about the lone survivor of a plague whose victims become vampires, a metamorphosis for which the novel, unlike the film, provides an ingenious medical explanation. Each night the survivor is besieged in his house by "vampires", and each day he kills as many as he can while they sleep. Finally, however, they succeed in trapping and killing him. The film has a reputation as being dreadful, but arguably it captures the brutalization of its hero in the human world's last gasp better than the remake, The Omega Man (1971), and it is certainly truer to the novel. The film truest to the novel's spirit, though with a different plot, is Night of the Living Dead (1968). [PN/JB]