© 2019 AEU Background: The effect of primary androgen deprivation therapy (ADT) in patients with localized prostate cancer (PCa) has not been well documented. The objective of the present study was to analyze the outcome of tumors treated with ADT as primary therapy in the Spanish Prostate Cancer Registry (19.4% of the series). Patients and methods: Patients were classified in three groups: 1) with low/intermediate risk clinically localized tumors; 2) with high risk and locally advanced (T3-4) tumors; 3) with metastatic tumors. Time to castration resistance and overall cancer-specific survival were analyzed. In non-metastatic tumors, survivals in patients treated with ADT were compared with data from patients who underwent local treatments from the Spanish Prostate Cancer Registry. Results: 703 cases were analyzed. There were significant differences in the time to castration resistance, which was lower in the group of metastatic tumors. During follow-up, there were 179 deaths (25.5%) of which 89 (12.6%) were due to PCa. After 3 years of ADT, only 14.6% of patients in group 1 had died (1% due to PCa), 20.5% in group 2 and 46.8% in group 3 (9.2% and 31.3% due to PCa, respectively). Cancer-specific survival was significantly worse in group 1 using ADT than radical prostatectomy or radiotherapy. In high-risk and locally advanced tumors, ADT also had a lower cancer-specific survival than local treatments. Conclusion: A longer time until the castration resistance was observed in patients with well- and intermediate-risk localized tumors treated with ADT. Patients with metastatic tumors showed the shortest time to castration resistance.