The perceived risk of HIV infection among clients of sex workers in brothels in Dar es Salaam is low. Measures of risky sexual behaviours and motives for buying sex were not associated with HIV risk perception among clients. Increasing the level of consistent and correct condom use both in transactional sex clients and FSWs in brothels is an urgent HIV prevention necessity in order to mitigate HIV transmission within the general population. Further research to evaluate risk perception in clients of FSWs in different contexts is warranted.