Context African Americans are disproportionately represented among those awaiting a transplant, but many are reluctant to donate their organs. Objective To test the effectiveness of using lay health advisors to increase organ donation among church members. Design Churches were pair-matched by average estimated income and size and then randomized to 1 of 2 interventions: one addressing organ donation and the other addressing increasing consumption of fruits and vegetables. Setting Twenty-two African American churches in Southeast Michigan. Patients or Other Participants Church members were trained to serve as lay health advisors (called peer leaders). Interventions Peer leaders conducted organ donation discussions with church groups and showed a DVD created for this program that was tailored to African American churches. Main Outcome Measures The primary outcome was verified registration in the state's donor registry. Participants also completed pre/post questionnaires regarding their attitudes about organ donation. Results Once clustering, baseline value, and demographics were adjusted for, the intervention and comparison groups did not differ on any of the 3 attitude scales on the posttest. In logistic regression analysis, with baseline donation status, demographics, and church clustering controlled for, the odds of self-reported enrollment at 1-year posttest did not differ by condition (odds ratio, 1.23; 95% CI, 0.87–1.72). A total of 211 enrollments in the state registry from participating churches were verified. Of these, 163 were from intervention churches and 48 were from comparison churches. Conclusions Use of lay health advisors through black churches can increase minority enrollment in a donor registry even absent change in attitudes.