Little is published about step-by-step implementation of telephone counseling interventions to promote community-based health activities. This article describes the authors' experience of implementing a church-based telephone mammography counseling intervention with peer counselors representing three principal racial or ethnic groups: African American, Latino, and Anglo (White). Twenty-six women from 12 churches in the Los Angeles area were recruited and trained to deliver the counseling annually over a two-year period to 570 women participants who were recruited from participating churches (n = 15). The counseling sessions were conducted from church-based telephone centers in key geographic locations in our program area. Training and supervision proved challenging: most of the Latino counselors had fewer than seven years of education and spoke only Spanish, while most of the other counselors had at least some college and spoke only English. Culturally specific and small group interactions, role plays, and a more modular approach to training were the most effective ways to enhance counselors' skills. Latina participants' mammography adherence rates were lowest, and their barriers reflected their low socioeconomic status; as Latina counselors shared basic information about mammograms and where to obtain them at little or no cost, the counseling exchanges tended to be nonconflictive and supportive. Black and White participants were generally more knowledgeable and adherent with screening guidelines than Latinas. We found that it was possible to implement this intervention with diverse groups and conclude with lessons learned that may inform others considering such a strategy.