Surgical endodontics was performed using an Er:YAG laser on 23 patients (4 males, 19 females) exhibiting periapical pathosis. After mucoperiosteal flap reflection, osteotomy was performed over the lesion using a low-speed dental engine with a round bur (#6-8). Root-end resection was then performed using an Er:YAG laser (100 mJ, 10 pps) with copious saline coolant. The root apex cavity for the retrograde root canal filling was prepared using either an ultrasonic device or Er:YAG laser. The clinical condition of the patients was evaluated at 1 week, 1 month, and 3 months after surgery. The mean irradiation time (+/-S.D.) for apicoectomy using the Er:YAG laser was 123.9+/-113.2 s. No adverse reactions were seen during the laser irradiation procedure, and no harmful sequelae were observed during the follow-up periods. It is concluded that apicoectomy using the Er:YAG laser would be both safe and practical. However, improvement of the laser device to limit the operation time would offer considerable advantages.