Abstract: Objective To observe the therapeutic effect and toxicity of fulvestrant on estrogen receptor (ER)-positive advanced breast cancer. Methods Twenty-seven patients who received fulvestrant treatment in our hospital from August 2011 to May 2012 were enrolled in this study. Their clinical data including the disease progression time, overall response rate, clinical beneficial rate, and side effects were analyzed. Results The median disease progression time, objective response rate, and 3-month clinical beneficial rate were 4.8 months, 14.81%(4/27), and 48.15%(13/27), respectively. The main side effects were fatigue and anorexia. Conclusion Fulvestrant is a well-tolerated and effective drug for ER-positive advanced breast cancer when it fails to respond to tamoxifen and aromatase inhibitors.