Background: The efficacy and safety of oral ulipristal acetate for the treatment of symptomatic uterine fibroids before surgery are uncertain. Methods: We randomly assigned women with symptomatic fibroids, excessive uterine bleeding (a score of >100 on the pictorial blood-loss assessment chart [PBAC, an objective assessment of blood loss, in which monthly scores range from 0 to >500, with higher numbers indicating more bleeding]) and anemia (hemoglobin level of ≤10.2 g per deciliter) to receive treatment for up to 13 weeks with oral ulipristal acetate at a dose of 5 mg per day (96 women) or 10 mg per day (98 women) or to receive placebo (48 women). All patients received iron supplementation. The coprimary efficacy end points were control of uterine bleeding (PBAC score of <75) and reduction of fibroid volume at week 13, after which patients could undergo surgery. Results: At 13 weeks, uterine bleeding was controlled in 91% of the women receiving 5 mg of ulipristal acetate, and 19% of those receiving placebo (P<0.001 for the comparison of each dose of ulipristal acetate with placebo). The rates of amenorrhea were 73%, and 6%, respectively, with amenorrhea occurring within 10 days in the majority of patients receiving ulipristal acetate. The median changes in total fibroid volume were −21%,, and +3% (P = 0.002 for the comparison of 5 mg of ulipristal acetate with placebo. Serious adverse events occurred in one patient during treatment with 5 mg of ulipristal acetate (uterine hemorrhage) and in one patient during receipt of placebo (fibroid protruding through the cervix). Headache and breast tenderness were the most common adverse events associated with ulipristal acetate but did not occur significantly more frequently than with placebo. Conclusions: Treatment with ulipristal acetate for 13 weeks effectively controlled excessive bleeding due to uterine fibroids and reduced the size of the fibroids.