Despite recent advances in imaging techniques, the staging process is still unsatisfactory in cancer of the prostate. The underestimation for stage B2 and C tumours in about 50%. We present our findings in a retrospective study analyzing the clinical and biological effects of complete androgen blockade before radical prostatectomy in patients with advanced stage localized tumours. We treated 21 patients from 1989 to 1993. All received preoperative homonotherapy by complete androgen block for at least 3 months before node dissection preceding suprapubic radical prostatectomy. Only 20 prostatectomies were performed as metastasis was found in the extemporaneous examination in 1 patient. The volume of the prostate gland had diminished in all patients after the hormonotherapy (27.8%) as did PSA (95%). When evaluated, the tumour stage of the surgical specimen was always more advanced than the needle biopsy. Only 1 tumour was strictly limited to the intracapsule and all the others had either invaded the capsule, reached the margins or had invaded the seminal vessels or lymph nodes. With a mean follow up of 45 months, recurrence rate is 50%, mainly due to tumours with positive margins or seminal invasion in patients who were not given adjuvant treatment. Our results are in agreement with those in the literature showing that although the volume of the prostate is reduced and PSA declines, no improvement in pathology staging is observed.