The main aim of this paper is to investigate the political determinants of international arms transfers. We distinguish between the decision to export arms (extensive margin) and the value of the arms exported (intensive margin). A theoretically-justified gravity model of trade augmented with political factors is estimated using a two-stage panel data approach for 104 exporting countries over the period of 1950 to 2007. For main political factors, we consider the level of democracy as well as the political orientation of the ruling governments in both of the trading partners. Furthermore, we account for political differences between trading partners, the political environment in their respective regions and the existence of military pacts. The main result indicates that political closeness between countries is an important determinant of arms transfers and that economic and strategic interests are not the only drivers.