Kevin Thomas of the "Los Angeles Times" wrote, "Directed by Butler and Robert Fiore, who is also the film's very adroit cinematographer, the witty and entertaining 'Pumping Iron' confronts what has been generally considered as a rather exotic subculture with the utmost sophistication. Butler and Fiore regard the bodybuilders with neither compassion nor ridicule but rather a steadfast, cool detachment—even when they themselves are being nakedly manipulative—which makes for a slick, shrewdly calculated, highly amusing and thoroughly enjoyable experience." Gary Arnold of "The Washington Post" called it "an amusing, buoyant documentary about competitive body building," and observed that "Schwarzenegger is the first personality since Bruce Lee who might become a unique and credible "physical" star, idolized in particular by kids but enjoyed and admired by a vast cross-section of the public." Louise Sweet of "The Monthly Film Bulletin" wrote that Schwarzenegger "inspires envy rather than disgust at ostentatious musculature, and lures even the reluctant viewer into his unusual world. Almost all the body-builders here are likable, but Schwarzenegger's articulateness and humour make the film cohere and convince."