Iron Man 2 easily topped the May 7 weekend box office with an estimated $133.6 million domestically, enough to qualify as the fifth-highest-grossing opening weekend of all time but quite a bit less than the record set by The Dark Knight in 2008 ($158.4 million).
The opening exceeded the 2008 debut of the first Iron Man ($98.6 million), BoxOfficeMojo reported.
Showings on 181 IMAX screens generated an estimated $10.2 million.
Iron Man 2 has also taken in $194 million overseas since it debuted in many international markets last week, bringing its worldwide total to more than $327 million, the Associated Press reported.
Last week's number-one movie, A Nightmare on Elm Street, saw its domestic gross fall a steep 72 percent to second place and an estimated $9.2 million, bringing its total to $48.5 million in 10 days.
The animated How to Train Your Dragon, meanwhile, saw its biggest decline yet, but still only dipped 36 percent to an estimated $6.8 million and third place for the weekend. Its domestic total is $201.1 million in 45 days.