A phase II study was performed to investigate the efficacy and tolerability of gemcitabine as third-line chemotherapy for patients with metastatic breast cancer, previously treated with both an anthracycline- and taxane-containing regimen. Twenty-three patients were treated with gemcitabine 1200 mg/m2 in a 30-min infusion on day 1, 8 and 15 of a 28 day cycle. Seventy-four percent of the patients had visceral metastases. No complete or partial responses were observed. Six patients (26%) had stable disease with a median duration of 4.0 months. The median time to progression was 1.9 months and the median survival time was 7.8 months. Neutropenia grade 3 and 4 was observed in four patients (18%). Non-hematological toxicity grade 3 included nausea and vomiting in 14%, skin toxicity in 9% and elevation of transaminases in 23% of the patients. Gemcitabine is ineffective as third-line single agent therapy in patients failing anthracycline and taxane treatment for metastatic breast cancer.