How does history affect HIV/AIDS prevalence in sub-Saharan Africa? This article studies the long-term historical determinants of prevalence at the subnational level, with a specific focus on the role played by historical missionary activities. On the one hand, missionaries were the first to invest in modern medicine in a number of countries, and these early health investments can have long-term positive effects. On the other hand, the impact of missionary activity is also negative effect through its effect on behaviors regarding sexual health and negative perception of condom use. The contemporary Christian response on abstinence and monogamy. Using contemporary individual-level data, we show that regions close to historical mission settlements are more likely to have a high HIV prevalence today. Among regions historically close to missionary settlements, proximity to a health investment is associated with lower prevalence rates and the negative efect can be explained by negative perceptions of condom use.