Alcohol consumption has been associated with high risk sexual behaviour among key populations such as female sex workers. We explored the drivers of alcohol consumption and its relationship to high risk sexual behaviour. Participants were drawn from a cohort of 1027 women selected from 'hot spots' in the suburbs of Kampala city. We conducted 3 in-depth interviews with 40 female sex workers between 2010 and 2011. Data were analysed thematically, focusing on alcohol use within the context of sex work. Alcohol consumption was very high with only seven women reporting that they did not drink. Alcohol consumption was driven by the emotional and economic needs of the participants, but also promoted by clients who encouraged consumption. Many sex workers only started drinking alcohol when they joined sex work on the advice of more experienced peers, as a way to cope with the job. Alcohol was blamed for unsafe sex, acts of violence and poor decision making which increased sexual and physical violence. Alcohol was reported to affect medication adherence for HIV-positive women who forgot to take medicine. The findings suggest that the drivers of alcohol consumption are multifaceted in this group and require both individual and structural interventions. Alcohol reduction counselling can be supportive at the individual level and should be an integral part of HIV prevention programmes for female sex workers and others such as patrons in bars. The counselling should be addressed in a sensitive manner to bar owners and managers.