The number of people visiting US cinemas during the summer months was the lowest since 1997, figures suggest.
Sir Ridley Scott's Kingdom of Heaven had been tipped to do well
Box office sales for the 18 weeks from early May through to September, reached an estimated $3.6bn (£1.9bn).
The figures - from box office tracker Exhibitor Relations - are down 9% on last summer.
Among this year's high-profile flops were The Island, starring Scarlett Johansson and Ewan McGregor, and the historical epic Kingdom of Heaven.
Other casualties of the summer slump included Ron Howard's Cinderella Man - starring Russell Crowe and Renee Zellweger - which failed to light-up the box office despite positive reviews.
Paul Dergarabedian, president of Exhibitor Relations, said: "This was a summer that really could be characterised as under a cloud from the beginning.
"Usually, the first weekend in May, you have a big film that kind of kicks off the summer. It didn't happen that way this time, and that was sort of an indicator of things to come."
Attendance figures were even bleaker than box office sales.
After higher admission price were taken into consideration, the number of film tickets sold are around 562.5m - down 12% on summer 2004.
March of the Penguins has been a surprise hit
However, summer 2005 did produce some big hits, led by Star Wars: Episode III - Revenge of the Sith, which took almost $380m (£205m).
Films at or near the $200m (£108m) mark included War of the Worlds, Batman Begins, Charlie and the Chocolate Factory, Wedding Crashers and Madagascar.
French documentary film March of the Penguins was also a surprise hit.
"In an ideal world, people would say 'OK, we have to think more creatively, we have to think outside the box and come up with new and different things'," said Steven Friedlander, head of distribution for Warner Independent Pictures.
"But I'm afraid what's going to happen is, we're all going to sit in a room and say 'We need more penguin movies'.
"So I don't really know what lessons we're going to take out of all this."