Assessed the effectiveness of 3 litter (L) control procedures on the grounds of a residential facility for the mentally retarded. 57 areas were divided into 5 groups according to the amount of L they contained. Daily L counts were made in 1 randomly chosen area for 4 groups, and weekly counts were made from 1 randomly chosen area from Group 5. After the baseline period, trash receptacles were placed at high traffic areas of the facility. This was followed by the payment of 2 resident workers for picking up trash. In the next phase, marked pieces of L were placed on the grounds, and a total of 130 residents voluntarily collected L and turned it in at a central location. When a marked piece was turned in, that S received $1.00 and had his or her picture taken and posted. This phase was followed by a return to the trash receptacles phase and then a return to the marked item phase. The marked item procedure reduced litter, but the use of trash receptacles and the payment of resident workers did not noticeably reduce the L.