Social reinforcement could be a variable that facilitates gambling behavior. Unfortunately, there are relatively few studies examining the impact that contingent social stimuli can have on betting behavior. Using simulated slot machine games and confederates, we investigated possible maintaining social contingencies for gambling with four recreational gamblers. Results indicated a small effect from a social positive reinforcement contingency for betting more credits than the previous trial. Four additional participants were recruited to replicate the effects of social positive reinforcement when structural aspects of the game were also changed, such as sound, win magnitude, and credit value. Lastly, one participant returned to the laboratory at a later time to examine the effects of different confederates providing social stimuli. This participant bet more in the presence of the confederate who had previously provided social positive reinforcement. Across the experiments, the social positive reinforcement contingency effect was replicated in five participants