The objective of this study was to identify racial differences in willingness to participate in a population with previous exposure to clinical research. A survey instrument was administered to community-dwelling whites and African Americans who were voluntarily receiving a lay research and health education newsletter from a local Boston geriatric clinical research institution. The survey instrument assessed willingness to participate in 3 hypothetical clinical trials (diet trial for obesity, medication trial for hypertension [HTN], chemotherapy trial for cancer). Surveys were received from 473 whites and 279 African Americans (53% response rate) with mean age 74 (SD +/- 9). In multivariate models, race was not significantly related to willingness to participate in the multivariate models for any of the 3 trials. Previous trial participation was related to a higher odds of willingness to participate in the diet trial only (OR 1.8, 95% CI 1.2, 2.6). Lower levels of trust in one's primary care physician were associated with a lower odds of willingness to participate in clinical trials for the diet and HTN trials (OR 0.5, 95% CI 0.3, 0.8 and OR 0.6, 95% CI 0.3, 0.9, respectively). These findings suggest that, within populations previously exposed to clinical research, African Americans are no less willing to participate in clinical trials compared to whites.