Prostatic cancer is the most frequently diagnosed neoplasm in men in the United States.’ As the longevity of the population increases in Western societies, so will the incidence of this already common malignancy. Thus, more men will be treated with androgen deprivation therapy, which is frequently used in advanced stages of the disease.2 While hypogonadism has been shown to cause osteoporosis, to date we have been unable to find a report linking androgen deprivation for prostatic cancer to osteoporosis in elderly men. We report 2 cases of hypogonadal osteoporosis after orchiectomy for adenocarcinoma of the prostate. In both cases osteoporosis was confirmed by conventional spinal radiographs and dual energy x-ray absorptiometry. The high bone turnover state after orchiectomy was suggested by increased biochemical markers of bone formation. Treatment with disodium etidronate and other inhibitors of bone resorption may slow the progression of osteoporosis in men after orchiectomy. We discuss the possible reasons why osteoporosis has not been described in elderly men after androgen deprivation for prostatic cancer and the role of preventive treatment in retarding the progress of osteoporosis in these men. CASE REPORTS