The most unique aspects of metastatic breast cancer is its hormonal respon-siveness, which can be exploited in the treatment of patients with this disease. Previously used modalitis such as adrenalectomy or hypophysectomy seem to have been replaced by nonsurgical management with aminoglutethimide. Another drug, tamoxifen, has now been widely accepted, in place of treatment with andro-gens, since it has a relatively low frequency of side effects. Progestins, such as medroxyprogesterone or megesterol, have also now established themselves as agents of endocrine therapy. Newer compounds are also now being tested. These would include leuprolide to achieve ovarian suppression; 4-hydroxyandrostene-dione, which is an aromatase inhibitor; buserelin, a luteinizing hormone releasing hormone agonist; and trilostane, a suppressor of adrenal steroidogenesis.