This open-label, multi-centre study will evaluate the safety, tolerability and effect on disease progression, survival time and Karnofsky performance status of bevacizumab (Avastin) in combination with taxane monotherapy in female patients with oestrogen-, progesterone- and HER2-receptor negative (triple-negative) breast cancer. Patients are eligible to participate in this study if they have not received prior chemotherapy for metastatic breast cancer and in the investigator's opinion, require combination therapy for treatment of their disease. Patients will receive taxane (weekly paclitaxel or three-weekly docetaxel) and bevacizumab (10 mg/kg every 2 weeks or 15 mg/kg every 3 weeks as intravenously infusion). The treatment will continue until disease progression. The target sample size is < 100 patients.