In this article the data on 652 primitive societies presented in Quincy Wright's A Study of War are analyzed by means of the techniques of multi-variate analysis and index- construction. Thirty-three percent of the societies are characterized as 'belligerent' in the sense that they are reputed to engage in aggressive warfare for economic or political purposes. An index of primitivity was constructed based on information on economic, political and social organization in the societies, and the level of belligerence varied from 0 percent at the most primitive level to 95 percent at the least primitive level, which corresponds roughly to what today is often referred to as 'traditional societies'. If in addition degree of contact with other societies is considered, the level of belligerenec varies from 0 percent in the most primitive and isolated societies to 100 percent in the least primitive and least isolated societies. These findings are then discussed.