Objectives: To assess the effect of neoadjuvant hormone treatment before radical prostatectomy on: tumor/prostate volume, prostate-specific antigen (PSA) and testosterone levels, surgical margin status and tumor stage, and the ease of surgery following treatment. Methods: Patients with clinically localized prostatic carcinoma were randomized to receive leuprolide acetate depot 3.75 mg once a month for 3 months and cyproterone acetate 300 mg once a week for 3 weeks prior to surgery (group A). A control group of patients had surgery without any pretreatment (group B). Results: 167 patients were evaluated for the efficacy parameters. In group A, 31% of patients had a reduction in tumor/prostate volume following hormone therapy. PSA and testosterone levels were significantly reduced (p = 0.0001) in patients in group A compared to basal values. Centralized histopathological data evaluated in 145 patients (group A and 75 group B) showed that more patients in group B had tumors at stages T3A and T3B than in group A; this difference was close to significance (p = 0.057). Positive surgical margins were more common in group B (60% of patients) compared to group A (39% of patients). Similarly lymph node involvement was more common in group B compared to group A (11 versus 3%). There was little difference between the 2 study groups for the other surgical parameters assessed (ease of dissection, duration of surgery, blood loss). Conclusions: Neoadjuvant hormone therapy before radical prostatectomy has some effects in the treatment of prostate cancer. However, long-term follow-up of patients is needed to assess the impact of this therapy on morbidity and mortality.