Metastatic breast cancer is a disease with a high mortality rate. Taxanes, a specific class of chemotherapeutic agents including Taxol® and Taxotere® have been demonstrated to be effective in tumor control and symptom relief in metastatic breast cancer patients. However, it was unclear whether there is a benefit in survival compared to non-taxane compounds. This study evaluated the effect of taxanes within the clinical setting during patients' individual courses of sequential treatments. Metastatic breast cancer patients were recruited from one practice of the University of Pittsburgh Cancer Institute Breast Cancer Program within the time frame of January 1999 to July 2005. Taxanes were beneficial for survival in women with metastatic breast cancer. However, the effect strongly depended on the estrogen receptor type. Patients who had metastatic breast cancer with negative estrogen receptors benefited enormously from taxane therapy. These results will assist clinicians in choosingthe best therapeutic regimes and may facilitate the development of guidelines for the management of metastatic breast cancer.