In this paper, we summarize the options of conservative systemic medical therapy in elderly patients with prostate cancer. Treatment was classified into three categories: 1) endocrine therapy, 2) systemic chemotherapy, and 3) treatment using other drugs. 1) The common endocrine therapy called CAB (combined androgen blockade) consisting of androgen ablation with medical or surgical castration using anti-androgen agents will be considered first. It is important to minimize or eliminate the side effects of hormonal therapy in elderly patients. Therefore,monotherapy with anti-androgen agents, intermittent CAB, watchful waiting and delayed CAB, sequential usage with LH-RH (luteinizing hormone-releasing hormone) and anti-androgens will be considered. In hormone refractory prostate cancer, estramustine may be administered as an estrogen effect is expected. 2) Recently, systemic chemotherapy such as docetaxel regimens has prolonged survival and chemotherapy should be considered as the next step. There are, however, a variety of controversial issues in elderly patients such as the suitable timing of induction and the optimal dose, interval and schedule. It is also unclear whether docetaxel alone should be administered or combined with estramustine, steroid or bisphosphonate. We have performed intermittent chemotherapy, consisting of docetaxel with estramustine, and this regimen has been tolerated well and resulted in a good quality of life. 3) Additional therapy such as steroids and bisphosphonate may be administered to improve the quality of life. We have listed the major treatment options for prostate cancer, reviewed the expectation induced by each treatment and outlined key issues pertaining to usage in elderly patients.