This project aims to research natural human population growth (excluding migration) in some of WWF’s priority places, by identifying the current stage of demographic transition in each and prevailing fertility and mortality rates. It also examines population growth rates, and other demographic and health factors. The aim of the analysis is to provide information to help WWF prioritize areas where it should focus future population-health-environment efforts as it scales up this approach within its priority places in the developing world. PHE approaches help improve access to voluntary family planning in areas where high population growth correlates with high priority for biodiversity conservation. Along with contributing to improving human health and local communities’ quality of life in parts of the world where few public or private sector entities are investing, slowing population growth may mitigate major and long-term threats to key habitats and their rare and endangered wildlife species. Results show statistically significant patterns of higher population growth, fertility and mortality rates, and lower demand for family planning within versus outside priority places and in rural versus urban areas.