Stimulating public-private partnerships (PPP) for health and economic development initiatives requires research that can answer key questions: (1) what are the health and economic returns likely to be realized; (2) over what time frames and with what certainty; (3) what investments are required to achieve results; and (4) what are the implementation strategies most likely to succeed. This presentation reviews ongoing research on the PPPs used to deliver public health services in the U.S., and explores the lessons this research offers PPPs in low and middle income countries. We examine how scientific evidence on public health delivery systems and their health and economic returns can be used to drive improvements and expanded investments in PPP.