Study Objective To compare the safety and effectiveness of the NovaSure impedance-controlled endometrial ablation system with hysteroscopic wire loop resection plus rollerball ablation for treatment of excessive uterine bleeding in premenopausal women. Design Randomized, multicenter, double-arm study (Canadian Task Force classification I). Setting Nine academic medical centers and private offices. Patients Two hundred sixty-five premenopausal women with symptomatic menorrhagia. Intervention Ablation performed with the NovaSure system or wire loop resection and rollerball. Measurements and Main Results Success [pictorial blood loss-assessment chart (PBLAC) score ≤75] was achieved in 88.3% of NovaSure-treated and 81.7% of rollerball-treated patients. One year after treatment 90.9% and 87.8%, respectively, reported normal bleeding or less (PBLAC ≤100) and 41% and 35%, respectively, experienced amenorrhea (PBLAC = 0). Mean procedure time was 4.2 minutes (average 84 sec) in the NovaSure group and 24.2 minutes in the rollerball group. Local and/or intravenous sedation was administered in 73% of NovaSure patients and 18% of rollerball patients. Intraoperative adverse events occurred less frequently with NovaSure (0.6%) than with rollerball (6.7%). Postoperative adverse events occurred in 13% and 25.3% of patients, respectively. Conclusion The NovaSure system was safe and effective in treatment of women with menorrhagia. The procedure is both quick and effective, and eliminates the expense and side effects of endometrial pretreatment.