The latest mock documentary by British comedian Sacha Baron Cohen took 30.4 million dollars (£18.9 million) in the first three days of release, beating Ice Age: Dawn of the Dinosaurs into second place.
Bruno follows the exploits of a flamboyantly gay Austrian fashion reporter as he attempts to make it big in America.
The movie has already caused controversy, with some of those duped by the character threatening legal action.
There has also been disquiet among some gay rights activists over the perceived negative way it portrays homosexuality.
On Friday, Jarrett Barrios, president of the Gay and Lesbian Alliance Against Defamation (GLAAD), said: “The movie was a well-intentioned series of sketches. Some hit the mark and some hit the gay community pretty hard and reinforce some damaging, hurtful stereotypes.”
Universal pictures, which distributes the film, has countered that the film is a satire that “uses provocative comedy to powerfully shed light on the absurdity of many kinds of intolerance and ignorance, including homophobia.”
Although taking an impressive 14.4 million dollars (£9 million) in sales on its opening Friday, box office returns tailed off over the next two days in an indication that Bruno may not have the staying power of Borat.
Paul Dergarabedian, box office analyst at Hollywood.com, said: “Normally you expect the film at least to be even on Saturday or above compared to Friday, because Saturday is the biggest movie-going day of the weekend. It is going to be interesting to see how it does over the long run.”