Oxaliplatin is a platinum compound that inhibits DNA synthesis. This drug has a broad spectrum of antineoplastic activity, and its results in breast cancer are promising. We began a phase II study in pretreated advanced breast cancer patients using oxaliplatin together with 5-fluorouracil and folinic acid, a combination based on the efficacy of both drugs in breast cancer and their different toxicity profiles. Seventeen patients with advanced breast cancer were treated with oxaliplatin, 5-fluorouracil, and folinic acid, and preliminary data were analyzed. The mean number of courses per patient was 2.82 (range 1-8). The main toxicity was gastrointestinal, with nausea and vomiting G2-3 in 53% of the patients. Hematologic toxicity was moderate with neutropenia G2-3 in 13% of the patients. Among 10 evaluable patients we obtained partial response in one and stabilized the disease in two patients. No data on survival were evaluated. The small number of enrolled and evaluable patients does not permit any conclusions to be drawn. The study is ongoing.