In western countries breast cancer is still the leading cause of death of women. Very promising results have been obtained by combining vinorelbine and doxorubicin, two of the most active drugs in metastatic breast cancer. However, despite the activity reported, this combination has shown a 10% rate of grade 2-4 cardiac toxicity, mainly due to the total cumulative doses of anthracycline delivered. The aim of this study was to divide the total dose of doxorubicin into two administrations on days 1 and 8, in order to cut down its toxicity while maintaining the same activity. Fifty-two chemotherapy naïve patients with metastatic breast cancer entered into the study and were treated with vinorelbine 25 mg/m2 plus doxorubicin 25 mg/m2 both on days 1 and 8 every three weeks. Fifty-one patients were eligible and evaluable for toxicity while 47 of them were evaluable for activity. Haematological toxicity was predominantly related to neutropenia, with grade 3/4 in 16% of cycles. Non-haematological toxicity was represented by alopecia grade 3 (which affected 65% of the patients), local phlebitis and severe constipation. No clinically significant cases of neuropathy or cardiac dysfunction were seen. With regard to activity, 38 out of 47 patients (80%) responded to therapy, nine of them achieving complete responses (19%). Median response duration was 16 months and the median overall survival was 22.7 months. We conclude that the fractionated administration of vinorelbine and doxorubicin is associated with excellent haematological and non-haematological tolerability (especially as regards cardiac toxicity), coupled with high levels of activity comparable to those observed using regimens based on unfractionated administration of treatment.