Although much drinking occurs in social settings, there has been little testing of alcohol in groups. The authors examined the effects of alcohol on performance on a group decision-making task. Fifty-four unacquainted male social drinkers were randomly assigned to 3-person groups that consumed either alcohol (0.82 g/kg) or a placebo. After drinking, participants decided whether to complete a 30-min questionnaire battery or toss a coin and, pending the outcome of that toss, complete either no questionnaires or a 60-min battery. Alcohol groups were significantly more likely than placebo groups to choose the coin toss. Results highlight the potent effects of alcohol on group decision making and suggest that application of social psychological theory and methods to the study of alcohol is warranted.