In preparation for the implementation of the Kenya AIDS Strategic Framework 2014/15-2018/19, the Kenya National AIDS and STI Control Programme facilitated a national polling booth survey as part of a baseline assessment of HIV-related risk behaviours among FSWs, MSM, and PWID, and their utilization of existing preventive interventions, as well as structural factors that may influence KPs' vulnerability to HIV. The survey was conducted among "key populations" (female sex workers, men who have sex with men, and people who inject drugs) to understand current HIV risk and prevention behaviours, utilization of existing programmes and services, and experiences of violence. In total, 3,448 female sex workers, 1,308 men who have sex with men, and 690 people who inject drugs were randomly selected to participate in polling booth survey sessions from seven priority sites. Survey responses were aggregated and descriptive statistics derived. In general, reported condom use among all key populations was quite high with paying clients, and lower with regular, non-paying partners. Many participants reported unavailability of condoms or clean injecting equipment within the past month. Exposure to, and utilization of, existing HIV prevention services varied significantly among the groups, and was reported least commonly by female sex workers. Encouragingly, approximately three-quarters of all key population members reported receiving an HIV test in the past three months. All key population groups reported experiencing high levels of physical and sexual violence from partners/clients, and/or arrest and violence by law enforcement officials. Although some of the findings are encouraging, there is room for improvement in HIV prevention programmes and services for key populations across Kenya.