Twelve patients with recurrent and metastatic breast cancer were treated with a combination of adriamycin and amsacrine (m-AMSA) to evaluate its efficacy and toxicity. Adriamycin was given at 40 mg/m2 i.v. and m-AMSA at 50 mg/m2 i.v. every 3 weeks. No response was observed. One patient received an escalated m-AMSA dose at 70 mg/m2 and the same dose of adriamycin. She died of treatment-related leukopenia and infection. We conclude that the combination of adriamycin and amsacrine at the dose and schedule used in our trial has little antitumor effect in the treatment of advanced breast cancer.