Three experiments provided evidence that intergroup bias occurs automatically under minimal conditions, using the Implicit Association Test (IAT). In Experiment 1, participants more readily paired in-group names with pleasant words and out-group names with unpleasant words, even when they were experienced only with the in-group and had no preconceptions about the out-group. Participants in Experiment 2 likewise showed an automatic bias favoring the in-group, even when in-group/out-group exemplars were completely unfamiliar and identifiable only with the use of a heuristic. In Experiment 3, participants displayed a pro-in-group IAT bias following a minimal group manipulation. Taken together, the results demonstrate the ease with which intergroup bias emerges even in unlikely conditions.