A great deal of work has been done over the last decade in the assessment of additive hormonal treatment approaches in women with advanced breast cancer. This work has been prompted by a number of factors which include: (1) the introduction of new hormonal agents, (2) increased knowledge of the physiologic actions of several hormonal agents, (3) the development of hormonal receptor assays to better predict the probability of hormonal responsiveness in a given patient, and (4) the apparent plateau in efficacy of cytotoxic chemotherapeutic approaches. The hormonal agents that have been studied most extensively in the recent past include tamoxifen (an antiestrogen), aminoglutethimide (an aromatase inhibitor), and medroxyprogesterone acetate (a progestin). In postmenopausal women, several agents exist that appear about equal in efficacy; but, currently, tamoxifen appears to be preferred as the initial hormonal treatment, primarily because of its low incidence of side effects. Studies involving combination hormonal therapy have produced interesting results, but further work is needed to establish superiority over tamoxifen alone. In premenopausal women, tamoxifen does have antitumor activity in some patients but has not been established as a replacement for oophorectomy. Properly conducted comparative trials will remain essential for the determination of the proper place of newer hormonal therapy approaches in clinical practice.