Taylor Swift won eight of 11 awards, including top artist.Taylor Swift has won eight awards at this year's US Billboard Music Awards.
The country pop singer won categories that included, Top Female Artist, Top Digital Songs Artist and Top Country Artist.
She said to the crowd: "You are the longest and best relationship I ever had."
Other winners included Justin Bieber for Top Male Artist and Top Social Artist and One Direction won Top Duo/Group and Top New Artist.
Electronic Dance MusicThe Billboard Music awards ceremony was hosted by comedian and 30 Rock star Tracy Morgan in Las Vegas, US. There were performances by Justin Bieber, Nicki Minaj, Selena Gomez, Chris Brown and Ed Sheeran.
Nominees are based on fan interactions with music. This includes album and digital singles sales, radio airplay, touring, streaming and social interactions on Facebook, Twitter, YouTube, Vevo, Spotify and other popular online destinations for music.
A demand for new music this year has meant Electronic Dance Music categories were added.
Top EDM Album went to Skrillex for Bangarang.
Top EDM Artist went to David Guetta. He said: "It's a wonderful moment of my life but I try to look at the future and do it again and again, you know."
Harlem Shake by Baauer won two awards for Top Dance Song & Top EDM Song.
Other Billboard Winners:
Top Hot 100 Song, Top Streaming Song Audio, Top Rock Song & Top Radio Song: Gotye feat. Kimbra Somebody That I Used To Know
Top Touring Artist, Top Dance Album & Top Dance Artist: Madonna
Top Rock Album: Mumford and Sons Babel
Top Digital Song & Top Pop Song: Carly Rae Jepsen Call Me Maybe
Top Streaming Song (Video): Psy Gangnam Style
Top Rap Song: Macklemore & Ryan Lewis feat. Wanz Thrift Shop
Top Rock Artist: Fun
Top Pop Album: Adele 21
Top Digital Songs Artist, Top R&B Album, Top R&B Song (Diamonds) & Top R&B Artist: Rihanna
Top Streaming Artist, Top Rap Album & Top Rap Artist: Nicki Minaj