To estimate the potential impact of an HIV/AIDS Vaccine in Kenya. Design: The Kenyan HIV/AIDS epidemic was modeled using the most current data from national sources including epidemiology and behavioral surveillance. The model’s baseline projection was validated against adult HIV prevalence at antenatal clinics and ge- neral population surveys. The model was used to analyze the effects of scaling up current pre- vention programs and adding potential HIV vac- cines with varying levels of effectiveness and coverage. Results: Even with full scale-up of currently available prevention, care and treat- ment programs, new infections will continue to burden Kenya. The introduction of a partially ef- fective AIDS vaccine could significantly alter the trajectory of the epidemic. Conclusion: The game changing impact that an AIDS vaccine could have on the AIDS epidemic in Kenya under- scores the importance of sustaining political support and financial investment to accelerate HIV/AIDS vaccine research and development.