Having previously won Best Action Game and Best Online Multiplayer at E3 in June, Battlefield 3 took Best of Gamescom at the European expo's public opening.
The modern-era shooter impressed at Electronic Arts' press conference and on the show floor.
Sony's upcoming handheld, the PlayStation Vita, replicated its E3 success by winning in the Best Hardware category.
FIFA 12 had been E3's Best Sports Game and became Gamescom's Best Console Game, while Diablo III was proclaimed Best PC Game.
Gamescom Awards 2011
Best of gamescom: Battlefield 3 (360 PC PS3)
Best Hardware or Accessory: PlayStation Vita
Best Console Game: FIFA 12 (360 DS iOS PC PS2 PS3 Vita Wii)
Best Mobile Game: Uncharted: Golden Abyss (Vita)
Best Online Game: Star Wars: The Old Republic (PC)
Best PC Game: Diablo III
Best Browser Game: The Sims Social (Facebook)
Best Family Game: Sesame Street: Once Upon a Monster (Xbox 360 Kinect)