Benign breast disease, aside from fibroadenomas and intraductal papillomas, frequently responds favorably to hormonal therapy. Although the use of estrogen, androgens, and progestogens often proves useful, danazol, in our hands, was found more consistently effective. Danazol, an impeded androgen derived from a progestogen, 17 alpha-ethinyltestosterone, was employed in doses of 100 to 400 mg/day for 3 to 6 months in the treatment of fibrocystic disease. This agent proved efficacious in eliminating nodularity in the majority of cases, with partial resolution in most of the others. Many women to whom surgery had been previously suggested were spared surgical interference because of a satisfactory response to danazol therapy.