Church-based health promotion (CBHP) interventions can reach broad populations and have great potential for reducing health disparities. From a socioecological perspective, churches and other religious organizations can influence members' behaviors at multiple levels of change. Formative research is essential to determine appropriate strategies and messages for diverse groups and denominations. A collaborative partnership approach utilizing principles of community-based participatory research, and involving churches in program design and delivery, is essential for recruitment, participation, and sustainability. For African Americans, health interventions that incorporate spiritual and cultural contextualization have been effective. Evidence indicates that CBHP programs have produced significant impacts on a variety of health behaviors. Key elements of CBHP are described with illustrations from the authors' research projects. Copyright © 2007 by Annual Reviews. All rights reserved.