In this prospective study, according to AJCC 1997 staging system T1-T3b histologically proven prostate adenocarcinoma patients were treated. Extracapsular extension, PSA≥ 10 ng/dL and gleason score 7 and above were considered as high risk criteria and in case one of them is positive, the patient considered in the high risk group, otherwise treated in low risk group. Low risk patients were administered neoadjuvant hormonotherapy with Triptorelin acetate 3.75 mg/month IM and siproterin acetate 300 mg/15 days IM for only 12 weeks and thereafter were given radiotherapy. In high risk patients, we continued on hormonotherapy for 24 weeks more after the termination of radiotherapy. A total dose of 70 Gy external radiotherapy with 200 cGy daily fraction doses was delivered, In this study the preliminary results of 50 patients who completed radiotherapy between January 1998 and December 2000 were given. The median age was 68 years (range 53-76). Their stages were distributed as follows: 21 (42%) T2a, 7 (14%) T2b, 18 (36%) T3a and 4 (8%). Twenty two patients had a gleason score above 6. Their pre-biopsy PSA levels ranged between 3,4 and 76.1 ng/mL (median 15 ng/mL). According to our risk criterias 10 patients were in the low risk group. Median follow up was 36 months. PSA levels measured before the initiation of radiotherapy were 0.02-16.7 ng/mL (median 1.05 ng/mL). This change in PSA levels before and after hormonotherapy was statistically significant (p<0.001). Prostate volumes that were measured at the beginning of therapy ranged between 15-105 cc (median 38 cc) and before radiotherapy were between 14.5-65 cc (median 28 cc). This volume change was also significant (p<0.001). Twelve patients had biochemical failures. Consequently two of six developed distant metastasis. Three patients died of prostate cancer, while 3 patients died of other medical diseases. Twenty two grade I, 18 grade II and 7 grade III acute rectal toxicity; 22 grade I, 23 grade II, 2 grade III acute urethral toxicity were observed according to RTOG/EORTC toxicity criteria. No serious late toxicity was observed in our patients who completed 6 months of follow up after radiotherapy. Neoadjuvant hormonotherapy seems to be effective in decreasing PSA levels and prostate volumes. The acute and subacute toxicities of this protocol also seem to be feasible.