Opening in second place was Disney's Martin Lawrence comedy "College Road Trip," which pulled in $14 million. Lawrence stars as an overprotective dad who tags along with his daughter (Raven-Symone) on her girls-only trek to choose a college.
Both movies put in decent numbers despite bad reviews.
"10,000 B.C." came in well behind the openings of past blockbusters from director Roland Emmerich ("Independence Day," "Godzilla"), whose best debut came four years ago with "The Day After Tomorrow" at $68.7 million.
"Those movies opened up in the summer. We're very strong for this time of year," said Dan Fellman, head of distribution for Warner.
Fellman said Emmerich's films tend to do better internationally, including "The Day After Tomorrow," which topped out at $186.7 million domestically and did nearly twice that business overseas.
"10,000 B.C." opened at No. 1 in 19 of its 20 foreign markets, among them Spain, Mexico, Germany and Australia, said Veronica Kwan-Rubinek, head of international distribution for Warner.
Overall business was off compared to the same time frame a year ago, an almost inevitable decline given that the blockbuster "300" opened with $71 million over that weekend in 2007, twice the haul of "10,000 B.C." The top-12 movies took in $91.8 million, down 34 percent from the same weekend last year.
It was the fourth straight weekend that revenues fell, cutting into a surge in movie-going earlier this year. Attendance is up just 0.5 percent so far in 2008 compared to a year ago, according to box office tracker Media By Numbers.
"The advantage we've been enjoying over the last couple of months has really taken a punch in the gut," said Paul Dergarabedian, Media By Numbers president.
The previous weekend's top flick, New Line Cinema's basketball comedy "Semi-Pro" starring Will Ferrell, tumbled to fourth place with $5.8 million. That brought its 10-day total to just $24.7 million, a poor showing for a Ferrell comedy.
Debuting at No. 5 was Lionsgate's heist thriller "The Bank Job," which opened with $5.7 million. Jason Statham stars as a former crook drawn back to a life of crime when he's lured into robbing a Lloyd's of London bank vault.
In narrower release, Focus Features' 1930s comedy "Miss Pettigrew Lives for a Day" opened with $2.5 million in 535 theaters for an average of $4,750 a cinema, compared to $10,478 in 3,410 theaters for "10,000 B.C." and $5,174 in 2,706 locations for "College Road Trip."
"Miss Pettigrew" stars Frances McDormand as a destitute British governess who bluffs her way into a gig as social secretary to a flighty American actress (Amy Adams).
Estimated ticket sales for Friday through Sunday at U.S. and Canadian theaters, according to Media By Numbers LLC. Final figures will be released Monday.
1. "10,000 B.C.," $35.7 million 2. "College Road Trip," $14 million 3. "Vantage Point," $7.5 million 5. "The Bank Job," $5.7 million 6. "The Spiderwick Chronicles," $4.8 million 7. "The Other Boleyn Girl," $4 million 8. "Jumper," $3.8 million 9. "Step Up 2 the Streets," $3 million 10. "Fool's Gold," $2.8 million.