To describe powered endoscopic dacryocystorhinostomy (DCR) with full sac exposure and primary mucosal anastomosis and report perioperative and follow-up results achieved with this procedure. Prospective, nonrandomized cohort study. Operative and postoperative data were prospectively collected on 36 unselected patients (15 men and 21 women; mean age, 62.4 y; range 14-91 y) who presented to a lacrimal clinic with epiphora and obstruction of the drainage of the nasolacrimal system and who consecutively underwent either primary or revision powered endoscopic DCR. A total of 47 procedures were performed; all were done by the same surgeon, who used a standardized surgical technique. Follow-up evaluations included symptom evaluation and endoscopic assessment of the newly created ostium with fluorescein testing at each postoperative visit. The only surgical complication was one case of orbital fat exposure. Forty-five of the 47 DCRs were patent after a mean follow-up of 11 months (standard deviation = 5 mo), yielding a success rate of 95.7%. Patency was assessed by endoscopic visualization of the ostium and fluorescein (initially placed on the conjunctiva) in the ostium. One of the 47 DCRs was a failure and one patient had O'Donaghue tubes in place with symptoms. Two patients with a patent ostium and positive results on fluorescein testing continued to have some symptoms. Powered endoscopic DCR with full sac exposure and primary mucosal apposition has a success rate comparable to that achieved with external DCR.