This brief is part of a series describing population, health and environment issues in distinct geographic areas in the Philippines. The Cagayan Valley region is faced with the challenge of preserving its natural resources as its agricultural and fishing industries expand. The Healthy Families, Healthy Forests Project carried out in collaboration with a local NGO, Process Luzon, and the local government to implement reproductive health and family planning (RH/FP) campaigns among communities with local health workers, who also promote improved natural resource management and forest conservation practices. The project has helped strengthen RH/FP services by building the capacity of local health workers, improving delivery of RH/FP supplies and related services, and increasing the awareness and use of contraceptives. Raising awareness of the links between population, health, and environment among policymakers, development planners, and project implementers is essential for greater cross-sectoral collaboration in Cagayan Valley and throughout the Philippines. An increased understanding of PHE links will lay the foundation for more effective, participatory development efforts that increase human well-being and sustain healthy environments.