Suture microvascular anastomosis is time-consuming and tedious and demands long and continuous training. The Unilink instrument system is a fast and simple method to achieve high patency rates without long and continuous training in the anastomosis of small vessels. The author experimentally studied the carotid arteries and facial veins of 14 rabbits with an average weight of 1900 gm using the unilink apparatus. A total of 27 arterial and venous anastomoses were performed. We examined the postoperative patency at immediate, 2 weeks, and 8 weeks. The results were as followings; 1. All anastomosed vessels were fully patent just after operation and at 2 weeks(100%), but one of the arterial anastomosis was thrombotized at 8 weeks(90%) 2. The mean time for completion of the anastomosis were 8.5 minutes(range 6-15) in arteries and 6.2 minutes.(range 4-10) in veins. 3. The cases having partial obliterations were 3 cases(15%) under the operating microscope. 4. At the histological examination, the thickness of vessel wall was decreased due to moderate atrophy of the media and mild degree of nonspecific chronic inflammation was seen around the unilink apparatus. 5. A case of the arterial anastomosis was released with acting out at 15 minutes after operation, and a case of arterial anastomosis showed complete oblieration at postoperative 8 weeks. 6. The important factors in the technical problems were the proper selection of the ring size and optimal fitting between two rings. The Unilink method provides a very safe, fast, and simple way to perform microvascular anastomoses.