Objective: To assess the outcomes of patients who underwent uterine fibroid embolization (UFE) and to evaluate factors associated with failure of UFE. Design: Retrospective study. Setting: University teaching hospital. Patient(s): Two hundred thirty-three consecutive patients who underwent UFE from November 1997 to February 2004. Intervention(s): Uterine fibroid embolizations were performed by three interventional radiologists using 355-500-μpolyvinyl alcohol particles. Main Outcome Measure(s): Hysterectomy rate, myomectomy rate, and repeat UFE rate. Result(s): With a mean follow-up of 13 months, a total of 22 patients underwent surgery after UFE (9.4%); 16 had hysterectomies (6.9%), and 6 had myomectomies (2.6%). This included 3 patients who underwent repeat UFE and subsequently required surgical intervention. The mean (±SEM) time interval between UFE and subsequent treatment was 12.5 ±2.0 months. Among patients who required surgery, 13 (59.1%) presented with recurrent menorrhagia, and 5 (22.7%) complained of persistent abdominal pain. Histopathologic examination revelead concomitant findings of adenomyosis in 25%of hysterectomy specimens. Patients who failed UFE were more likely to have had a previous myomectomy (13%vs 2.4%) and significant reduction in the uterine size 6 months after UFE (57.1%vs 25.2%). Conclusion(s): The overall failure rate of UFE is 9.4%. Failure is mainly due to persistent menorrhagia and abdominal pain. Shrinkage of the uterus after UFE does not necessarily correlate with long-term success of UFE.