A package -culling conveyor system and a method for culling flat packages from a bulk flow of flat and non-flat packages. The conveyor system includes a tilted conveyor belt (24) conveying flat packages while non-flat packages tumble off its lower side. A high - friction conveying surface or a raised barrier along the length of the conveying surface of the tilted conveyor belt (24) holds flat packages on the tilted belt. The separated packages are more fully culled in a conveyor comprising a roller conveyor belt (36) with belt rollers (38) rotated in a direction to push packages sidewise toward a culling element that extends along the belt's length. Culling elements include powered rollers (55) or vertical walls forming side guards. The culling elements block the non-flat packages from exiting off the side of the belt so that they are conveyed off the end of the belt separate from the flat packages.