Twenty-seven metastatic breast adenocarcinoma patients, pretreated with standard hormonotherapy or chemotherapy, received carboplatin 100 mg/m2/day x 3 intravenously (i.v.) plus etoposide 100 mg/m2/d x 3 i.v. repeated at 4-week intervals. There were five partial responses (18.5%), two minor responses, and 12 disease stabilizations. The dominant metastatic disease sites were soft tissue in three partially responding patients and visceral metastases in the two remaining responders. The median duration of response and time to progression were, respectively, 10 and 26 weeks. Major toxicity was myelosuppression with 85% of patients developing leukopenia; 48%, anemia; and 30%, thrombocytopenia. Carboplatin plus etoposide has shown antitumor activity in our group of pretreated patients. Based on the same schedule, a first-line carboplatin plus etoposide Phase II trial has been started.