Ninety-six patients were entered into a randomised, double-blind, double-dummy, clinical trial to assess the efficacy and safety of fadrozole as compared to megestrol acetate as second-line hormonal treatment for patients with advanced breast cancer. Analysis of results was on an intention-to-treat basis and included response rate, time to progression (TTP), time to treatment failure (TTF) and survival. Forty-six patients received fadrozole and 50 were randomised to megestrol acetate. Patients and pretreatment prognostic variables were balanced in the two arms of the trial. The objective response rates [3/46 (7%) for fadrozole and 3/50 (6%) for megestrol acetate], TTP, TTF and survival were similar in the two arms of the trial. Toxicity was also similar in the two arms of the trial and consisted mainly of oedema, hypertension and minor gastrointestinal symptoms. Fadrozole appears to be as active as megestrol acetate in second-line hormonal treatment of advanced breast cancer.