Koro is generally considered a culture-bound psychiatric syndrome, the dominant feature of which is anxiety or dissociation. A close examination of koro epidemics in China, where koro cases appear to be more frequent than other parts of the world, shows that koro has a sociocultural component which has not been sufficiently taken into account in previous formulations. This article analyzes koro in the natural environment in which it appears and dispels the notion of koro being individual psychopathology. Koro, at least the way it is manifested in China, is a social malady maintained by cultural beliefs which affect the whole community and not just those diagnosed with it. Further directions for research into the subject are discussed.