A total of 22 patients with locally advanced prostate cancer (stage B2 to C) was entered into a protocol for 3 months of preoperative hormonal deprivation. Of the patients 8 were judged to have clinical stage B2 and 14 to have stage C disease. The protocol regimen consisted of daily administration of flutamide (250 mg. orally 3 times per day) and leuprolide injection (7.5 mg. intramuscularly) every month. Patients with objective evidence of downstaging by prostate specific antigen (PSA) levels and transrectal ultrasound were offered surgical therapy. Of the 22 patients 20 have completed the protocol and are evaluable, and 2 of them did not show significant downstaging and elected radiotherapy. Preoperative hormonal therapy produced an average 33% downsizing of the prostate gland as determined by transrectal ultrasound volumetrics. Decreases in serum PSA values were demonstrated from a pre-hormonal average of 30 micrograms./l. (range 0.7 to 97.7) to an average of 0.53 micrograms./l. (range 0.2 to 5.7) after hormonal therapy. Of the 18 patients who underwent an operation after demonstrating significant downsizing 7 had pathologically confirmed stage B disease, 7 had stage C cancer and 4 had positive pelvic lymph nodes. Of the 8 clinical stage B2 cancer patients 3 had pathological stage B2 disease following the protocol. Of the 12 clinical stage C cancer patients 3 had pathological stage B disease, 4 had positive pelvic lymph nodes and the remainder had pathological stage C cancer. Thus, only 3 of 20 patients (15%) demonstrated pathological downstaging from the clinical stage. Downsizing the prostate volume and PSA changes with hormonal therapy were not predictive of patient outcome either alone or in combination. Preoperative hormonal therapy did not appear to facilitate the surgical procedure. Patients completing neoadjuvant hormonal therapy had an average estimated blood loss of 1,238 ml. and an average operating time of 183 minutes. A group of 20 consecutive patients with stage B2 prostate cancer who underwent radical prostatectomy without preoperative hormone therapy had an average estimated blood loss of 1,296 ml. and an average operating time of 171 minutes.