Gemcitabine and epirubicin were evaluated in metastatic breast cancer (MBC) patients to determine the maximum tolerated dose (MTD), efficacy, and toxicity of the combination. Patients initially received 800 mg/m(2) of gemcitabine (days 1 and 8) and 50 mg/m(2) of epirubicin (day 1) every 21 days. Each dose level had three to eight patients. Phase II used the dose level preceding the MTD. Forty-eight patients enrolled without reaching MTD; therefore, phase II used the highest dose level (1500 mg/m(2) of gemcitabine, 90 mg/m(2) of epirubicin). After 23 patients (group A) experienced hematologic toxicities and frequent dose reductions, 15 received 1250 mg/m(2) gemcitabine (days 1 and 4) and 90 mg/m(2) epirubicin (day 1) every 21 days (group B). Out of 38 patients, 46% responded (group A 32%, group B 67%). Median response duration was 8.5 months; median time to progression 8.4 months; and median time to treatment failure 4.8 months. Gemcitabine and epirubicin are well tolerated and active in MBC patients, and the group B regimen warrants further investigation.