OBJECTIVE We assessed the incidence of high-grade prostatic intraepithelial neoplasia (HGPIN) in prostates removed for bladder cancer, and evaluated its correlation with preoperative serum prostate specific antigen (PSA). METHODS We reviewed the histology of the prostate from men who underwent cystoprostatectomy for bladder cancer without known prostate pathology prior to surgery. Preoperative serum PSA levels in patients with HGPIN were analyzed. RESULTS 61 cystoprostatectomy specimens from May 1992 to April 1999 were reviewed. High-grade prostatic intraepithelial neoplasia (PIN) was found in 46/61 (75%) of the prostate specimens, including 21/21 (100%) patients with prostatic cancer, and 25/40 (63%) patients without prostatic cancer. The mean serum PSA in men with PIN without evidence of prostatic adenocarcinoma was 1.9 ng/mL (SD=2.026). CONCLUSIONS The incidence of isolated high-grade PIN was 63%. The presence of high-grade PIN does not result in a significant elevation of serum PSA.