Androgen deprivation based on hormone manipulation is the treatment of choice in advanced prostatic cancer. The unequivocal role of adrenal androgens in the growth of prostatic cancer after medical or surgical castration requires a new logical approach (complete androgen blockade) in the treatment of advanced prostate cancer. One hundred and fifty patients with biopsy-proven advanced prostatic cancer were randomized into two groups. One group (74 patients) received leuprolide + flutamide (complete androgen blockade); the second group (76 patients) received only leuprolide and, during the first 3 weeks of treatment, cyproterone acetate (150 mg/day) to prevent flare-up phenomena. The aim of the study was to evaluate the differences between the two groups on overall survival and time to progression (log-rank test). One hundred and twenty-five patients were evaluable, 62 in the leuprolide-only group and 63 in the leuprolide + flutamide group. Median duration of follow-up was 102 weeks. No statistical difference between the two groups was observed in overall survival, in time to disease progression, and in time to treatment failure. In the combination (leuprolide + flutamide) treatment group, a positive trend for overall survival and in time to progression was observed in a subgroup of patients with good performance status and no bone metastases. We observed mild gastrointestinal toxicity (diarrhea, nausea) in the group treated with leuprolide + flutamide. The aim of this study was to compare the effectiveness of total androgen withdrawal with medical testicular suppression in advanced prostatic cancer. No significant statistical difference was observed between the two groups in overall survival and in time to progression, but probably too few patients were enrolled in each treatment arm to give a statistical interpretation of our results. We conclude that there is a positive trend in the combination treatment arm in patients with good prognostic factors.