Investigated the effects of litter already present within an area on littering behavior in a forest setting for a period of 4 successive Fridays. The 1st and 3rd Fridays were used to obtain an estimate of the amount of litter that accumulated after the areas were cleaned of litter (the nonlittered condition). During the 2nd and 4th Fridays all litter was removed from the area, then 60 pieces of litter were scattered throughout the picnic site (the littered condition). The number of pieces of litter was counted each Saturday morning. Results show that the amount of litter found on Saturday mornings following a littered condition was always less than the amount of litter found following a nonlittered condition. In those areas which were littered, people had a tendency not to discard additional litter.