The couple's celebratory night started with dinner for 50 family and friends at Simon at Palms Place, a hotel rep confirmed to Access Hollywood.
Guests of the happy couple included Antonio "LA" Reid, Steve Bartles, Tyrese Gibson, Sanaa Lathan & Floyd Mayweather.
The dinner party had tables covered in candles and a sign that read "Happy Anniversary Mariah & Nick."
Guests enjoyed surf & turf with sides of macaroni & cheese and mashed potatoes. For dessert, the party dined on creme brulee and chocolate chip cookies.
Following dinner, Mariah & Nick moved the party to the Moon Nightclub inside the fantasy tower at the Palms. Nick surprised his wife with a video of some of the great moments from their first year together, followed by the release of 1000 balloons into the Las Vegas sky.
Nick also found time to keep the party going from the DJ booth as their guests danced.
The lovely evening was capped off with a toast to the happy couple and the cutting of a five-tiered cake.
Mariah and Nick married in a in a surprise ceremony in the Bahamas. The couple kept the news of the wedding secret from even their guests, who came down to the island expecting something else.
Related Content from AccessHollywood.com:
PLAY IT NOW: Mariah Carey & Nick Cannon Celebrate First Anniversary In Las Vegas (May 1, 2009)
PLAY IT NOW: 2009 Sundance Film Festival: Mariah Carey Talks 'Push'