The Omega Man (1971)

Due to an experimental vaccine, Dr. Robert Neville is the only survivor of an apocalyptic war waged with biological weapons. The plague caused by the war has killed everyone else except for a few hundred deformed, nocturnal people calling themselves 'The Family'. During the day, he roams through the vacant city. At night, he fends off a bloodthirsty horde of mutant scavengers garbed in Spanish inquisition robes and sunglasses, led by Matthias, a former television newscaster in his good ol'; pre-mutant days.