It is generally known that littering can not be controlled by merely physical technology but by controlling the littering behavior of individuals. This would seem to be the most important factor of control. As one effective technique for controlling littering behavior, a behavior modification technique has recently been discovered. This study evaluates the effectiveness of such a behavior modification technique to induce littering behavior in a naturalistic settings: the baseball stadium. The procedures used were as follows; (1) an operant contingency in the form of positive reinforcement procedures, (2) a positive prompting strategy, (3) a negative prompting strategy, (4) a litter bag only condition. The findings revealed a highly significant effect of treatment. There were significant differential effects between the different treatment strategies.