We reviewed the surgical specimen from 142 men undergoing radical prostatectomy for prostate cancer detected because of an elevation in serum prostate specific antigen alone. No patient had a palpable abnormality suggestive of cancer. One patient had no identifiable tumor in the radical prostatectomy specimen, 8 (6%) had only a few high power microscopic fields showing cancer, 40 (28%) had an estimated tumor volume of less than 1 cc and 93 (65%) had a tumor volume of greater than 1 cc. Surgical margins were positive in 37 patients (26%) and negative in 105 (73%). Most patients with cancer detected because of modest elevation in prostate specific antigen, even without palpable abnormalities, have a clinically significant tumor volume and are good candidates for radical prostatectomy.