We reviewed retrospectively the medical records of 70 patients treated for prostate cancer who were followed for more than 10 years or until they died. All patients were treated by hormonal therapy and 54 of 70 patients (77 per cent) were combined with castration. Of 70 patients 10 (14.3 per cent) are alive now with an average follow up for 180.5 months. Of 60 patients with stage A and B only 3 died of the tumor. Of 56 patients with stage C and D, 10 and 18 patients died of the tumor, respectively. From the point of pathology, none of the patients with well differentiated adenocarcinoma died of the tumor. And in patients with stage A and B, pathologically well and moderately differentiated adenocarcinoma, there were no cancer death. On the other hand, a group of patients of poorly differentiated adenocarcinoma had a poor prognosis. In cases with well differentiated adenocarcinoma who discontinued hormonal medication (diethylstilbestrol diphosphate) no patients died of the tumor. From these observations we consider that, after long term hormonal medication, we can stop the hormonal medication for patients who have no positive prostate biopsy results for 4 years with well differentiated adenocarcinoma of stage A and B.