The aim of this study was to assess the efficacy and toxicity of an idarubicin-prednimustine combination in advanced breast cancer. 19 patients received idarubicin 35 mg/m2 day 1 and prednimustine 100 mg/m2 days 2-6, every 21 days. Three objective responses with a median duration of 7 months were observed. Tolerance was good. A further 23 patients were given idarubicin administered at 15 mg/m2 days 1, 2 and 3 and prednimustine at the aforementioned dosage. 8 (35%) showed an objective response (4 CRs, 4 PRs) with a median duration of 6 months. No severe toxicity was observed. Results suggest activity of idarubicin-prednimustine combinations in advanced breast cancer, and further studies are indicated since this regimen is easily administered, especially to elderly patients.