Participatory evaluation can be an essential tool for community-based organizations in tailoring programs to the needs of the populations they serve. This article provides a case study of Salud Sí, a promotora-driven health promotion program designed to encourage physical activity, fruit and vegetable consumption, and stress reduction among Mexican American women. Through a partnership between a community health center and an academic institution, we describe how the participatory evaluation framework is applied over a 10-year period throughout the stages of program development, implementation, and sustainability. Partners used the results to identify the essential elements of the health promotion program.