The powerful movie about a US Army bomb disposal squad in Baghdad blew away the competition, with film-maker Kathryn Bigelow becoming the first woman ever to win the Oscar for best director.
- Click for complete list of winners[break]
"This really is, there´s no other way to describe it, the moment of a lifetime," said Bigelow, only the fourth woman ever to be nominated for the best director award by Academy voters.
"I´d like to dedicate this to the women and men in the military who risk their lives in a daily basis in Iraq and Afghanistan and around the world," Bigelow added. "May they come home safe."
The top acting honors went to Hollywood veterans Jeff Bridges for his performance as an alcoholic country singer in "Crazy Heart" and Sandra Bullock, for her role as a feisty housewife in the sports drama "The Blind Side."
It was a perfectly scripted night at the Kodak Theater for Bigelow, whose low-budget film had been locked in a duel with "Avatar," the science-fiction epic directed by her ex-husband James Cameron.
Cameron´s phenomenally successful blockbuster -- the highest-grossing film in history with more than 2.5 billion dollars in earnings -- finished the night with three Oscars in mostly technical categories.
The face-off between Bigelow and Cameron´s films had been billed as the "Battle of the Exes" but the two film-makers smiled and joked throughout the evening as they sat just a few feet apart throughout the show.
The acting awards largely followed the form-book, with Bridges finally landing an Oscar after four previous unsuccessful nominations.
Bridges thanked his late parents in an acceptance speech which came 39 years after his first Oscar nomination.
"Thank you mum and dad for turning me on to such a groovy profession," said a delighted Bridges, who had earlier welled up with tears after a moving tribute from Michelle Pfeiffer.
Bullock meanwhile completed a uniquely dubious double with her best actress award, which came just 24 hours after she was crowned worst actress at the Razzies, the annual eve-of-Oscars parody.
"Did I really earn this or did I just wear you all down?" said Bullock, whose Oscar-winning role was based on the true story of Leigh Anne Tuohy, who took in a homeless black teenager Michael Oher and helped set him on the road to an American football career.
Bullock dedicated her win to "the moms that take care of babies and children no matter where they come from."
The supporting actor awards went to Austria´s Christoph Waltz for his portrayal of a sadistic Nazi officer in Quentin Tarantino´s "Inglourious Basterds," and Mo´Nique, a monstrous parent in harrowing drama "Precious."
Mo´Nique´s triumph made her only the only the fifth black actress in history to win an Oscar after Hattie McDaniel, Whoopi Goldberg, Halle Berry and Jennifer Hudson.
The 42-year-old paid tribute to trailblazing "Gone With the Wind" actress McDaniel in her acceptance speech.
"I want to thank Miss Hattie McDaniel for enduring all that she had to so that I would not have to," Mo´Nique said.
Waltz meanwhile was in raptures after collecting his statuette from Spanish siren Penelope Cruz.
"Oscar and Penelope -- that´s uber bingo," a delighted Waltz said. "There´s no way I can ever thank you enough but I can start right now -- thank you," Waltz added.
"Up," about an elderly gent who ties balloons to his home to live his dream of seeing the wilds of South America, took the award for best animated feature.
Earlier hosts Steve Martin and Alec Baldwin kicked off the proceedings with a wise-cracking intro which saw several nominees introduced from the audience in a revamped format to the show.
Spotting "The Hurt Locker" director Bigelow and former spouse James Cameron, Martin couldn´t resist a gag.
"She was so pleased to be nominated with (Cameron) she sent him a gift basket with a timer," Martin said.
"He reciprocated by sending her a Toyota," Baldwin chimed.
Oscars 2010 Winners:
Best Picture: The Hurt Locker
Best Director: Kathryn Bigelow (The Hurt Locker)
Best Actor in a Leading Role: Jeff Bridges (Crazy Heart)
Best Actress in a Leading Role: Sandra Bullock (The Blind Side)
Best Actor in a Supporting Role: Christoph Waltz (Inglourious Basterds)
Best Actress in a Supporting Role: Mo´Nique (Precious)
Best Original Screenplay: Mark Boal (The Hurt Locker)
Best Adapted Screenplay: Geoffrey Fletcher (Precious)
Best Foreign-Language Film: El Secreto de Sus Ojos (The Secret in Their Eyes) - Argentina
Best Animated Feature Film: Up
Best Original Score: Michael Giacchino (Up)
Best Documentary: The Cove
Best Film Editing: Bob Murawaski & Christ Innis (The Hurt Locker)
Best Visual Effects: Joe Letteri, Stephen Rosenbaum, Richard Baneham & Andrew R Jones (Avatar)
Best Cinematography: Mauro Fiore (Avatar)
Best Sound Mixing: Paul N.J. Ottoson & Ray Beckett (The Hurt Locker)
Best Sound Editing: Paul NJ Ottosson (The Hurt Locker)
Best Costume Design: Sandy Powell (The Young Victoria)
Best Art Director: Rick Carter & Robert Stromberg (art direction) & Kim Sinclair (for set direction) (Avatar)
Best Make-up: Star Trek
Best Documentary Short: Music by Prudence
Best Live Action Short Film: The New Tenants
Best Animated Short Film: French Logorama
Best Original Song: Ryan Bingham & T-bone Burnett for The Weary Kind (theme from Crazy Heart)
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