Switzerland faces an HIV epidemic that is concentrated among certain groups, including migrants from high‐prevalence countries. This study explores the HIV/AIDS knowledge of professionals providing asylum and integration services at cantonal level, with a view to optimising the role they can play in HIV prevention. Data was collected by means of a self‐administered questionnaire; 266 of the 368 professionals (72%) approached responded. Answers were analysed with regard to the respondent's sex, age, workplace and geographical location. General HIV/AIDS knowledge is sound, although there are deficits regarding the vulnerability of migrants. Staff working for non‐governmental organisations are significantly more likely (39%) to attach high importance to HIV/AIDS than civil servants (25%). They are also significantly more likely to have undergone training in HIV/AIDS (25% compared with 15%). Respondents from the German parts of Switzerland are significantly more likely (75%) than those from Romandie and Tessin (48%) to feel sufficiently well informed to be able to address the HIV/AIDS needs of migrants.Professionals providing asylum and integration services could be familiarised more systematically with HIV/AIDS policy documents and with the HIV/AIDS projects and materials in place for migrants. There is also scope to institutionalise targeted training and knowledge management opportunities better.