Threat has been linked to conformity, but little is known about the specific effects of different kinds of threat. We test the hypothesis that perceived threat of infectious disease exerts a unique influence on conformist attitudes and behavior. Correlational and experimental results support the hypothesis. Individual differences in Perceived Vulnerability to Disease predict conformist attitudes; these effects persist when controlling for individual differences in the Belief in a Dangerous World. Experimentally manipulated salience of disease threat produced stronger conformist attitudes and behavior, compared with control conditions (including a condition in which disease-irrelevant threats were salient). Additional results suggest that these effects may be especially pronounced in specific domains of normative behavior that are especially pertinent to pathogen transmission. These results have implications for understanding the antecedents of conformity, the psychology of threat, and the social consequences of infectious disease. Copyright © 2011 John Wiley & Sons, Ltd.