LOS ANGELES — Martin Scorsese's mob epic ''The Departed'' won best picture at the Academy Awards on Sunday and earned the filmmaker the directing prize that had eluded him throughout his illustrious career.

''Could you double-check the envelope?'' said Scorsese, who arguably had been the greatest living American filmmaker without an Oscar.

He received his Oscar from three contemporaries and friends, Steven Spielberg, Francis Ford Coppola and George Lucas. ''So many people over the years have been wishing this for me.''

In an evening when no one film dominated as the Oscars shared the love among a wide range of movies, three of the four acting front-runners won: best actress Helen Mirren as British monarch Elizabeth II in ''The Queen''; best actor Forest Whitaker as Ugandan dictator Idi Amin in ''The Last King of Scotland''; and supporting actress Jennifer Hudson as a soul singer in ''Dreamgirls.''

The other front-runner, Eddie Murphy of ''Dreamgirls,'' lost to Alan Arkin for ''Little Miss Sunshine.''

''For 50 years and more, Elizabeth Windsor has maintained her dignity, her sense of duty and her hairstyle,'' said Mirren, who has been on a remarkable roll since last fall as she won all major film and television prizes for playing both of Britain's Queen Elizabeths.

''She's had her feet planted firmly on the ground, her hat on her head, her handbag on her arm and she's weathered many many storms. ... If it wasn't for her, I most certainly wouldn't be be here. Ladies and gentlemen, I give you the queen,'' Mirren said, holding her Oscar aloft.

Arkin played a foul-mouthed grandpa with a taste for heroin ''Little Miss Sunshine,'' a low-budget film that came out of the independent world to become a commercial hit and major awards player.

''More than anything, I'm deeply moved by the open-hearted appreciation our small film has received, which in these fragmented times speaks so openly of the possibility of innocence, growth and connection,'' said Arkin.

Hudson won an Oscar for her first movie, playing a powerhouse vocalist who falls on hard times after she is booted from a 1960s girl group. The role came barely two years after she shot to celebrity as an ''American Idol'' finalist.

''Oh my God, I have to just take this moment in. I cannot believe this. Look what God can do. I didn't think I was going to win,'' Hudson said through tears of joy. ''If my grandmother was here to see me now. She was my biggest inspiration.''

''Little Miss Sunshine'' also won the original screenplay Oscar for first-time screenwriter Michael Arndt.

The film follows a ghastly but hilarious road trip by an emotionally messed-up family rushing to get their darling girl (10-year-old supporting-actress nominee Abigail Breslin) to her beauty pageant.

''When I was a kid, my family drove 600 miles in a VW bus with a broken clutch,'' Arndt said, describing a road trip that mirrored the one in the film. ''It ended up being one of the funnest things we did together.''

The nonfiction hit ''An Inconvenient Truth,'' a chronicle of Al Gore's campaign to warn the world about global warming, was picked as best documentary.

''People all over the world, we need to solve the climate crisis. It's not a political issue. It's a moral issue,'' Gore said, joining the film's director, Davis Guggenheim, on stage.

''An Inconvenient Truth'' also won original song for Melissa Etheridge's ''I Need to Wake Up.''

''Mostly, I have to thank Al Gore for inspiring me, showing me that caring about the earth is not Republican or Democrat, it's not red or blue. We are all green,'' Etheridge said.

Earlier, Gore appeared with best-actor nominee Leonardo DiCaprio to praise organizers for implementing environmentally friendly practices in the show's production.

DiCaprio set up a gag with Gore, asking the 2000 presidential candidate if there was anything he wanted to announce.

''I guess with a billion people watching, it's as good a time as any. So my fellow Americans, I'm going to take this opportunity here and now to formally announce my intentions ...,'' Gore said, his voice trailing away as the orchestra cut him off.

Composer Gustavo Santaolalla won his second straight Oscar for original score for ''Babel,'' a film ''that helped us understand better who we are and why and what we are here for,'' he said. He won the same prize a year ago for ''Brokeback Mountain.''

The dancing-penguin musical ''Happy Feet'' won the Oscar for feature-length animation, denying computer-animation pioneer John Lasseter (''Toy Story'') the prize for ''Cars,'' which had been the big winner of earlier key animation honors.

''I asked my kids, 'What should I say?' They said, 'Thank all the men for wearing penguin suits,''' said ''Happy Feet'' director George Miller.

The savage fairy tale ''Pan's Labyrinth'' took three Oscars. The Spanish-language film won for art direction, makeup and cinematography.

''To Guillermo del Toro for guiding us through this labyrinth,'' said art director Eugenio Caballero, lauding the writer-director of ''Pan's Labyrinth,'' the tale of a girl who concocts an elaborate fantasy world to escape her harsh reality in 1940s Fascist Spain.

Germany's ''The Lives of Others,'' about a playwright and his actress-girlfriend who come under police surveillance in 1980s East Berlin, won the foreign-language Oscar, the films it beat including ''Pan's Labyrinth.''

''Letters From Iwo Jima'' won the sound-editing Oscar for Alan Robert Murray and Bub Asman. Murray's father was an Iwo Jima survivor.

''Thank you to my father and all the brave and honorable men and women in uniform who in a time of crisis have all made that decision to defend their personal freedom and liberty no matter what the sacrifice,'' Murray said.

The record holder for Oscar futility, sound engineer Kevin O'Connell, extended his losing streak to 19 nominations without a win. This time, O'Connell and two colleagues were nominated for sound mixing on ''Apocalypto,'' Mel Gibson's portrait of the savage decline of the ancient Mayan empire, but they lost to another trio of sound engineers that worked on ''Dreamgirls.'' ''Apocalypto'' lost in all three categories in which it was nominated, all for technical achievements.

Once an evening of back-slapping and merrymaking within the narrow confines of Hollywood, the Academy Awards this time looked like a United Nations exercise in diversity.

The 79th annual Oscars feature their most ethnically varied lineup ever, with stars and stories that reflect the growing multiculturalism taking root around the globe.

''What a wonderful night. Such diversity in the room,'' said Ellen DeGeneres, serving as Oscar host for the first time, ''in a year when there's been so many negative things said about people's race, religion and sexual orientation.

''And I want to put this out there: If there weren't blacks, Jews and gays, there would be no Oscars,'' she said, adding: ''Or anyone named Oscar, when you think about that.''



Oscar winners

Complete list of winners at the 79th annual Academy Awards, presented Sunday night at the Kodak Theatre in Los Angeles:

Best Motion Picture: "The Departed"

Lead Actor: Forest Whitaker, "The Last King of Scotland"

Lead Actress: Helen Mirren, "The Queen"

Supporting Actor: Alan Arkin, "Little Miss Sunshine"

Supporting Actress: Jennifer Hudson, "Dreamgirls"

Directing: Martin Scorsese, "The Departed"

Foreign Language Film: "The Lives of Others," Germany

Adapted Screenplay: William Monahan, "The Departed"

Original Screenplay: Michael Arndt, "Little Miss Sunshine"

Animated Feature Film: "Happy Feet"

Art Direction: "Pan's Labyrinth"

Cinematography: "Pan's Labyrinth"

Sound Mixing: "Dreamgirls"

Sound Editing: "Letters From Iwo Jima"

Original Score: "Babel," Gustavo Santaolalla

Original Song: "I Need to Wake Up" from "An Inconvenient Truth," Melissa Etheridge

Costume: "Marie Antoinette"

Documentary Feature: "An Inconvenient Truth"

Documentary Short Subject: "The Blood of Yingzhou District"

Film Editing: "The Departed"

Makeup: "Pan's Labyrinth"

Animated Short Film: "The Danish Poet"

Live Action Short Film: "West Bank Story"

Visual Effects: "Pirates of the Caribbean: Dead Man's Chest"

Jean Hersholt Award (Oscar statuette): Sherry Lansing.

Honorary Academy Award (Oscar statuette): Ennio Morricone.