Malaria and HIV are two major threats to maternal and child health in Africa. Highly effective prevention technologies exist, such as insecticide-treated bednets, prophylactic drugs for malaria, and antiretroviral prophylaxis against mother-to-child transmission of HIV, but they remain unused by most African mothers. I designed and implemented an NGO program that provided free insecticide-treated bednets to pregnant women conditional on their enrolment at a prenatal clinic. The program increased the uptake of prenatal care services by 117%, which in turn generated an 84% increase in the uptake of HIV testing services by women and a 59% increase in the number of follow-up visits at the prenatal clinic. This suggests that pregnant women acquire information on available preventive drugs and services during their first visit to a clinic. Thus, by ensuring that pregnant women come for the first visit, a conditional transfer can be used to cost-effectively increase the take-up of preventive health services. In areas of intense malaria transmission and high HIV prevalence, providing free treated nets to pregnant women through prenatal clinics could save the lives of 18 babies per 1,000 pregnancies at a cost of US $441 per child life saved