Serum prostate-specific antigen (PSA) has greatly enhanced our ability to detect carcinoma of the prostate. Yet, because of its lack of specificity for malignancy, approximately two thirds of the men with an elevated PSA level do not have prostate cancer. This problem is particularly relevant to men whose prostate feels normal by digital rectal examination (DRE) and appears normal by transrectal ultrasound (TRUS). Carcinoma of the prostate, if detected in these men, is staged as T1c and is usually considered to be of clinical significance. Attempts at refining PSA have included attempts to correct the serum level relative to the size of the prostate (PSA density). Although conflicting data has been reported in the literature, it appears when stratified for PSA ranges between 4 and 10 ng/mL, PSA density does not provide an advantage over PSA alone in cancer detection in patients with a normal DRE and TRUS.