Docetaxel (Taxotere) has been intensively investigated for the treatment of metastatic breast cancer, where it has proved to be one of the most active agents. Initial phase II studies in anthracycline-resistant metastatic breast cancer demonstrated impressive response rates that have been confirmed in phase III randomized trials. Docetaxel remains the only single agent to demonstrate a survival benefit in anthracycline-resistant patients. More recently, the combination of docetaxel with capecitabine (Xeloda) has demonstrated additional improvement in survival over docetaxel alone in a randomized phase III trial. In patients previously treated with an alkylating agent, docetaxel is the only single drug to demonstrate improved efficacy over doxorubicin in a randomized trial. Docetaxel has been investigated in combination with the anthracyclines doxorubicin and epirubicin in randomized trials. The docetaxel-containing regimens have consistently demonstrated improvement over the non-docetaxel-containing regimens. The efficacy and safety of weekly docetaxel has extended the line of investigation for combinations with agents normally administered on a weekly basis, such as vinorelbine [Navelbine], gemcitabine [Gemzar], and trastuzumab [Herceptin], with promising findings. In addition, the results of the triple-drug combination of docetaxel, a platinum salt (cisplatin or carboplatin), and trastuzumab have resulted in impressive response rates and time to progression in a population of metastatic breast cancer patients with HER2/neu-positive tumors. The consistent demonstration of a high level of efficacy with manageable toxicity ensures the continued widespread investigation of docetaxel in metastatic breast cancer.