Compañeros en la Salud (Partners in Health) is a 3-year project funded by the National Cancer Institute to conduct a church-based health promotion program whose aim is to reduce the risk of breast, cervical, and diet-related cancers in Latino/Hispanic women by increasing their knowledge of preventive behaviors, motivating healthy behavior change, and increasing their access to and utilization of preventive health services. From a systems perspective, churches serve as miniature, dynamic communities that present an opportunity for developing and implementing a program of health promotion. An analysis of church, Promotora (peer health worker), and participant characteristics from the preintervention base-line data revealed a naturally occurring segmentation of churches by congregation size and denomination. The Catholic churches almost exclusively were larger, whereas the Protestant churches almost exclusively were smaller. An analysis of the psychosocial characteristics of the various Latino women, when stratified by church congregation size, revealed that the women from the smaller, Protestant churches were poorer, had a lower level of acculturation, and had lower lifetime rates of clinical breast examinations. These results suggested greater resource deficits and a relatively higher need for Promotora outreach services for women from the smaller, Protestant churches. Implications are presented for differential approaches to effective health promotion among various types of churches.