At the film review aggregator website Rotten Tomatoes, "The Omega Man" received mixed reviews, with a combined average positive score of 65% from 34 critics. Howard Thompson gave a mostly negative review in "The New York Times", saying "the climax is as florid and phony as it can be," while A.D. Murphy of "Variety" described the film as "an extremely literate science fiction drama." Roger Ebert awarded two stars out of four and found the mutants "a little too ridiculous to quite fulfill their function in the movie." Gene Siskel of the "Chicago Tribune" gave the film one star out of four, writing that director Boris Sagal "must have resembled a juggler trying to keep four dramatic balls aloft. About midway through the film, the balls started bumping into each other, Sagal began to stumble, and by the time the crew was completing the final scene, Sagal was on the floor with the balls bouncing wildly away from his grasp." Kevin Thomas of the "Los Angeles Times" wrote that the film was "strictly a potboiler, but it's without pretensions and never runs dry. Director Boris Segal has captured some stark apocalyptic images and gotten some suitably vivid performances. Most importantly, he keeps things moving so fast that there's not enough time to ponder credibility gaps big enough to fly a Boeing 747 through." Tom Shales of "The Washington Post" wrote, "Director Sagal displays no great affinity for science fiction — he's from TV land — but he generally upholds interest and can certainly handle the shocks and suspense, which are both abundant and enjoyable in a Saturday matinee way."