Abstract: The present invention is a vehicle-mounted trommel screening apparatus. A rotating trommel screen cage having an open front and a closed back is mounted on the vehicle so that the open front of the trommel screen cage is at a side of the vehicle and is adjustably tiltable about the vehicle side while the cage rotates. A conveyor is mounted below the trommel screen cage to convey material rearwardly off the end of the trailer. A push plate folds down below the trommel to assist in loading material that has been discharged from the front. Axially extending gussets within the cage provide additional lifting and tumbling action. Material is dumped into the trommel screen cage with the cage tilted back from the open end. The rotation of the cage causes a tumbling action which simultaneously breaks up larger pieces of material and screens smaller material to the conveyor below the screen. Material retained in the trommel screen may be dumped by tilting the trommel screen cage forward toward the open end.