STUDY OBJECTIVES To determine the safety and efficacy of endometrial resection, and to provide an indicator of the operative problems and treatment outcomes. DESIGN Prospective study. SETTING Academic practice tertiary care setting. PATIENTS One hundred twenty-six consecutive women undergoing endometrial resection because of menorrhagia, who wished to retain their uterus. INTERVENTION Hysteroscopic endometrial resection performed as a day procedure. MEASUREMENTS AND MAIN RESULTS In 126 women, 2 cases of uterine perforation were readily identified on the operating monitor screen; they had no serious sequelae. Three patients had heavy uterine bleeding, which was controlled by intrauterine tamponade. No women had other serious complications. CONCLUSION Hysteroscopic endometrial resection is a safe, successful, and cost-effective treatment of menorrhagia.