Ludacris, whose real name is Christopher Bridges, was out of town at the time of the Wednesday night fire.
Fulton County Fire Department spokesman Gregory Chambers says a relative was in the basement of the main residence when the fire started and was not injured.
Chambers says the fire was put out within 30 minutes but destroyed the pool house, which he says is larger than most homes.
The fire was being investigated but the cause was not immediately identified.
Ludacris won a Grammy for best rap album for "Release Therapy" and best rap song for "Money Maker."