Our study comprehensively examined the factors that facilitate or hinder participation in prostate cancer trials by examining patients attitudes, physicians perceived barriers, characteristics of prostate trials and sites, and broader community indicators. The main objectives were to: a) Conduct telephone interviews with prostate cancer patients (Asian, Black, Latino, and White) identified through the California Cancer Registry (CCR), who were treated at or reside within 60 miles of trial sites to assess their discussions with physicians, intentions and actual participation in prostate cancer clinical trials, attitudes and knowledge about such trials, and barriers to and facilitators of participation, b) Conduct a self-administered survey of the physicians who care for, and were identified by the participating patients as their most influential physician, to determine their typical clinical trial counseling and referral practices, attitudes, and their perceived barriers to and facilitators of patient recruitment, c) Conduct a telephone survey with a research team member (RTM) from each prostate cancer clinical trial site within three regions of the California Cancer Registry (CCR) to assess its cultural competence and outreach efforts, and d) Identify and link clinical trial site community indicators to the clinical trial and patient data collected. FINDINGS: The RTM survey indicated RTMS believe that most prostate cancer patients do not participate in clinical trials, particularly minority patients. The patient survey indicated greater patient willingness to participate in a prostate control trial in men with less than a high school education and men with governmental health insurance. The most frequently reported barriers to recruitment were that patients did not understand what participation involved and patients were unable to take time off.