Forty-four evaluable patients with breast carcinoma previously treated with combination chemotherapy consisting of cyclophosphamide, methotrexate, and 5-fluorouracil (CMF) were treated with a combination chemotherapy regimen consisting of doxorubicin (A) (20 mg/m2 on days 1, 8, 15, and 22, repeated every 28 days) and mitomycin (MIT) (10 mg/m2 on day 1, repeated every 28 days). Five patients (11%) achieved a complete remission (CR) and 14 patients (32%) had a partial response (PR). The median duration of survival was 11.5 months and the median duration of response was 8 months for responders (CR and PR). Toxicity was moderate and consisted of neutropenia (74%), thrombocytopenia (25%), pneumonitis (11%), and cardiomyopathy (2%). The combination chemotherapy regimen A and MIT is an effective regimen for treating previously treated with CMF.