Objectives To estimate HIV prevalence and associated risk factors among men who have sex with men (MSM) in Dar es Salaam, Tanzania following the implementation of the national comprehensive package of HIV interventions for key population (CHIP). Design A cross-sectional survey using respondent-driven sampling. Setting Dar es Salaam, Tanzania's largest city. Participants Men who occasionally or regularly have sex with another man, aged 18 years and above and living in Dar es Salaam city at least 6 months preceding the study. Primary outcome measure HIV prevalence was the primary outcome. Independent risk factors for HIV infection were examined using weighted logistics regression modelling. Results A total of 777 MSM with a mean age of 26 years took part in the study. The weighted HIV prevalence was 8.3% (95% CI: 6.3%-10.9%) as compared with 22.3% (95% CI: 18.7%-26.4%) observed in a similar survey in 2014. Half of the participants had had sex with more than two partners in the month preceding the survey. Among those who had engaged in transactional sex, 80% had used a condom during last anal sex with a paying partner. Participants aged 25 and above had four times higher odds of being infected than those aged 15-19 years. HIV infection was associated with multiple sexual partnerships (adjusted OR/AOR, 3.0; 95% CI: 1.8-12.0), not having used condom during last sex with non-paying partner (AOR, 4.1; 95% CI: 1.4-7.8) and ever having engaged in group sex (AOR, 3.4; 95% CI: 1.7-3.6). Conclusion HIV prevalence among MSM in Dar es Salaam has decreased by more than a half over the past 5 years, coinciding with implementation of the CHIP. It is nonetheless two times as high as that of men in the general population. To achieve the 2030 goal, behavioural change interventions and roll out of new intervention measures such as pre-exposure prophylaxis are urgently needed.