The medical records of 84 postmenopausal women treated with oral norethisterone acetate (NTA) for advanced breast cancer have been analyzed retrospectively. Treatment was devoid of significant toxicity. 21 patients were not evaluable for treatment response, either due to insufficient data or inadequate tratment trial. Among the 63 evaluable patients, complete plus partial response was obtained in 21 (33.3%) with a median duration of 10 months. Disease stabilization was observed in 16 patients (25.4%) for a median duration of 5 months, while 26 patients (41.3%) showed progressive disease while on treatment. The best response was observed in women with predominantly soft tissue metastases (CR + PR: 34.9%) and aged over 70 (CR + PR: 48%). The literature on norethisterone acetate is reviewed and compared with the present results. The role of progestational agents in the treatment of advanced mammary carcinoma is discussed.