AbstractTransrectal ultrasonography (TRUS), digital rectal examination (DRE), and quantification of serum prostate‐specific antigen (PSA) are accepted and evaluated methods for detecting prostate cancer. Positive predictive values (PPV) of DRE and TRUS are low, and only slightly enhanced when used in combination with PSA. PSA lacks sufficient sensitivity and specifity to be used alone as a screening test for prostate cancer. The parameters PSA‐density and PSA‐velocity make PSA a better tumor marker, but they are not reliable on an individual basis. Age‐specific reference ranges have the potential to make PSA a more sensitive tumor marker for men less than 60 years of age and a more specific one for men beyond 60 years. With currently available diagnostic methods approximately 10% of patients undergoing transurethral or open resection of the prostate for presumed benign prostatic hyperplasia will have carcinoma detected in the histologie material. In 392 patients successively treated in our clinic for presumed BPH and thoroughly investigated to exclude prostatic carcinoma (DRE, TRUS, biopsy when PSA>4 ng/ml or PSA‐D>0.15), the tumor was found incidentally in 4%. Another finding in this study was the detection of prostatic carcinoma by random biopsy in patients without a palpable or visible tumor by imaging and without PSA increase (>4 ng/ml). Biopsies were performed because of a hypoe‐choic zone in the opposite lobe which turned out to be negative. Such tumors cannot be properly classified in the current TNM system. Treatment options for patients with incidental prostatic carcinoma are age‐ and stage‐dependent. Patients less than 60 years old may be treated with a curative approach, irrespective of the T category (Tla or Tib); patients with a life expectancy longer than 10 years and a pTlb incidental carcinoma likewise should be offered a curative therapy. © 1995