Tween sensation Justin Bieber was four for four at the awards. The 16-year-old became the youngest person to win the artist of the year award. He also beat Eminem and his mentor, Usher, for favorite pop/rock male.
"I can't stop smiling; this is amazing. Truly I don't know how this is possible because I've been singing Eminem since I was three and Usher is my mentor. So this is big," said Bieber.
Bieber also won favorite pop/rock album and the show's breakthrough artist award.
Usher took the first award of the night, beating out Alicia Keys and Sade for best R&B/Soul album of the year. Usher also won for favorite male for R&B/Soul. Rihanna took home best female Soul/R&B.
The Black Eyed Peas also got an early award, winning best pop/rock band, duo or group.
The show celebrates all different genres of music, including country, where a very humble Brad Paisley was named favorite male artist.
"When you're up here accepting an award, it doesn't mean you are the best, it just means you lucked out and gone down that path that got you up on stage and I'm pretty mindful of that. I try to keep that perspective," said Paisley.
Last year's entertainer of the year, Taylor Swift, sparkled on stage as she thanked her fans for her favorite female country award.
In the adult contemporary category, the award went to previous winner Michael Buble.
"It's not easy, the stress of knowing that in years to come this will all be gone and I'll be selling this on eBay fills me with dread, at the same time that I'm excited," Buble joked backstage.
The show was packed with performances.
Rihanna, performing with ruby-red hair, kicked off the show with a medley of songs from her latest album, "Loud."
Kid Rock gave an emotional performance of "Times Like These," a song lifting up his hometown of Detroit during its recent economic struggles.
Katy Perry had the evening's most explosive performance as pyrotechnics accentuated her performance of her latest song, "Firework."
Bieber sang his inspirational song, "Pray."
Swift sang "Back to December," but incorporated some of OneRepublic's "Too Late To Apologize" at the end of her performance.
Country music trio Lady Antebellum and rapper Eminem were the leading nominees with five nominations each. Both acts had two of the year's top hits - Eminem with "Love The Way You Lie," featuring Rihanna, and Lady Antebellum, with "Need You Now."
Other nominees include rapper B.o.B, Drake and the music from the hit TV show "Glee," Sade.
The Associated Press contributed to this report.