Political sociologists have focused considerable attention on the extent to which corporate elites are politically unified. Few studies, however, have examined the extent to which corporations oppose one another. This study examines the determinants of corporate political conflict by focusing on the extent to which pairs of firms contributed to opposing Congressional candidates in the 1980 elections. Using a sample of 1,596 dyads created by relations among 57 firms, several hypotheses about the effects of interfirm social and economic relations on political opposition are tested.Variables found to decrease the likelihood of political opposition included common stockholdings, director interlocks with the same financial institutions, membership in the same primary industry, and market constraint relations between the industries in which firms produce. The findings are consistent with arguments that suggest the importance of social and economic networks in deterring conflict among firms.