In order to evaluate the efficacy of two different sequences of second and third line hormonotherapy in advanced post-menopausal breast cancer, 257 women aged 36-91 years (mean age: 63.6 years) who had become resistant to tamoxifen (TAM), entered into a multicenter randomized trial comparing two different regimens: 1) Aminoglutethimide (Ag) 500 mg/day with hydrocortisone supplementation from 30 to 60 mg/day; and 2) oral medroxyprogesterone acetate (MPA) 500 mg twice a day. 250 patients were evaluated following second line hormone therapy and, after cross-over, 128 following third line hormonotherapy. No significant difference was observed, during either second or third line therapies, for toxicity, survival, or response rate; however, in both second and third line therapies the median time to progression was significantly longer with Ag therapy.