The novel chemotherapeutic agent paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) has received more attention than perhaps any other drug in the past two decades in its development for the treatment of breast cancer. Its unique mechanism of action, demonstrated safety profile, and significant antitumor activity in thousands of patients treated in clinical trials thus far have led to recent US Food and Drug Administration approval of its use against chemotherapy-refractory metastatic breast cancer. This report will summarize the series of clinical investigations with paclitaxel in patients with metastatic breast cancer that have been completed over the past 3 years at Memorial Sloan-Kettering Cancer Center and address present and future avenues of research.