Sutureless end-to-end anastomosis of rat common carotid artery was carried out, low energy Nd-YAG laser being used thereby. An intraluminal-intervascular splint, made of water-soluble poval, was used for precise adaptation of the intimas. Neither stay suture nor glue was required. The patency rate of the anastomosed vessels, 24 hours after operation, was as high as 91%. The vessels were confirmed to be likewise patent on the 7th and 30th postoperative day. Complications such as pseudoaneurysm formation or stenotic change, were negligible. The fusion of the anastomosis with Nd-YAG laser was histologically proved to be satisfactory and the result of tensile strength test was excellent. Temperature at the anastomotic site during laser irradiation was measured, optimal energy for anastomosis determined and possible mechanism of vascular fusion by laser beam postulated. The major advantages of the laser technique combined with poval splint, such as rapidity, consistency and no residual foreign body (thread or adhesive), are discussed.