Research on African societies documents the magnitude of the AIDS epidemic, and shows that at younger ages women are more likely to be affected than men. Young African women are particularly vulnerable to HIV infection because sexual relations with men are an important means to achieve social and economic status, and for some women they are necessary for survival. Many African adolescents and young adults engage in premarital sexual relationships, either sequentially or simultaneously. Unmarried African males commonly have a 'main' girlfriend whom they expect to marry, and one or more other girlfriends, for whom there are no such expectations; some females have similar strategies. This study uses focus-group data from Cameroun to describe popular types of premarital sexual relationships, and to examine gender differentials in the motivations for engaging in such relationships and in perceptions of the factors that affect the marriage prospects of these premarital relationships. Economic need leads many young women to use premarital sexual relations for economic support, despite high levels of HIV infection. These findings help inform policy-makers and program managers in Africa about gender differentials in the motivations for engaging in premarital sexual unions, which in turn can help improve the design and implementation of social and health policies and programs.