Three hundred sixty-two men underwent transrectal ultrasound of the prostate (TRUS), digital rectal examination (DRE), and serum prostate-specific antigen (PSA) determination as part of an early detection program for prostate cancer. Thirty-seven (10%) cancers were detected. DRE had the highest sensitivity and specificity, 89 percent and 84 percent, respectively. TRUS and PSA had comparable sensitivities (84% and 81%) and specificities (82% and 82%). The positive predictive values of DRE, TRUS, and PSA determination were 39 percent, 35 percent, and 33 percent, respectively. We found a cancer detection rate of 16 percent among patients with symptoms of bladder outlet obstruction and 5 percent in patients without these symptoms. The detection rate was 36 percent for physician-referred patients and 3 percent for self-referred patients. This suggests to us that at the present time the best utilization of medical resources to increase prostate cancer detection is to educate men to have annual medical evaluations by primary-care physicians who are encouraged to incorporate risk assessment and screening DRE as part of their routine practice. Any man with either abnormal findings on examination or increased risk should be referred to a urologist for further evaluation.