Elected national representatives make decisions to fund health programmes, but may lack skills to interpret evidence on health-related topics. In 2011, we surveyed the 61 members of Botswana's Parliament about their use of epidemiological evidence, then provided two half-days of training about using evidence. We included the importance of counter-factual evidence, the number needed to treat, and unit costs of interventions. A further session in 2012 covered evidence about the HIV epidemic in Botswana and planning the best mix of interventions to reduce new HIV infections. The 27 respondents reported they lacked good quality, timely evidence, and had difficulty interpreting and using evidence. Thirty-six, including seven ministers, attended one or both trainings. They participated actively and their evaluation was positive. Our experience in Botswana could potentially be extended to other countries in the region to support evidence-based efforts to tackle the HIV epidemic.