Little is known about the background of commercial sex workers in Africa. This study investigated how women in a trading town on the trans-Africa highway in southwest Uganda become involved in commercial sex work, which factors contribute to their economic success or lack of success, and what effect life trajectories and economic success have on negotiating power and risk behaviour. Over the course of two years detailed life histories of 34 women were collected through recording open, in-depth interviews, the collection of sexual and income and expenditure diaries, visits to the women's native villages, and participant observation. The women share similar disadvantaged backgrounds and this has played a role in their move into commercial sex. They have divergent experiences, however, in their utilisation of opportunities and in the level of success they achieve. They have developed different life styles and a variety of ways of dealing with sexual relationships. Three groups of women were identified: (1) women who work in the back-street bars, have no capital of their own and are almost entirely dependent on selling sex for their livelihood; (2) waitresses in the bars along the main road who engage in a more institutionalised kind of commercial sex, often mediated by middlemen and (3) the more successful entrepreneurs who earn money from their own bars as well as from commercial sex. The three groups had different risk profiles. Due partly to their financial independence from men, women in the latter group have taken control of sexual relationships and can negotiate good sexual deals for themselves, both financially and in terms of safe sex. The poorer women were more vulnerable and less able to negotiate safer sex. A disadvantaged background and restricted access to economic resources are the major reasons for women gravitating to commercial sex work. Various aspects of personality play a role in utilising income from commercial sex to set up an economic basis that then makes the selling of sex unnecessary. This has implications for interventions, and part of the longer-term solution should lie in improving the economic position of women vis-à-vis men.