This paper examines the central role of ethnology, the science of race, in the administration of colonial India. This occurred on two levels. First, from the late eighteenth century onwards, proto-scientists and administrators in India engaged with metropolitan theorists through the provision of data on native society and habits. Second, these same agents were continually and reciprocally influenced in the collection and use of such data by the political doctrines and scientific theories that developed over the course of this period. Among the central interests of ethnographer-administrators was the native criminal and this paper uses knowledge developed about native crime and criminality to illustrate the way science became integral to administration in the colonial domain.