In 1960 Jacobson and Suarez introduced the operating microscope to vascular surgery and demonstrated the superiority of small vessel repair using magnification. The first clinical replantation of an arm in the western world was performed by Malt in 1962, and Komatsu and Tamai reported the successful replantation of a completely amputated thumb in 1965. To perform a digit or hand replantation, microsurgical anastomosis of blood vessels is absolutely essential to revascularize the severed part. Without accurate repair of bone, nerves and tendons in addition to vascular anastomosis, however, it is impossible to gain functional success when replanting a digit or hand. This is a difficult task because all structures must be reconstructed at the same level and time. Even if the repair of some structures has been postponed, the secondary reconstruction may also be troublesome due to circular scarring at the replantation level. Since replantation surgery has been popularized throughout the world in recent years, the replantation sucess rate has increased and the surgeons interest in functional reconstruction of replanted digits or hands has been stimulated. The authors have seen and studied 6 cases of upper Jimb and 20 cases of finger replantation from May, 1980 through January, 1982 at the department of orthopedic surgery, Yonsei University College of Medicine. The results were as follows: I. The average age was 20 years and the male to female sex ratio was 4.5:1. 2, The causes of injury are detailed as follows: electric saw(6); cutting machine(5); roller(4}; presser(2); stone(2); others(3). 3. The level of amputation in 26 replantations was as follows: thumb, 3 cases; index finger, 4 cases; middle finger, 9 cases; ring finger, 4 cases; palm, I case, wrist, 3 cases; forearm, 1 case; upper arm, 1 case. 4. The maximum ischemic times for successtul results were 16 hours in limb replantation and 22 hours in finger replantation. 5. Six limbs, with four complete and two incomplete amputations, have been replanted and all six limbs survived: Twenty digits, with nine complete and eleven incomplete amputations, have also been replanted and 6.5 cases of nine complete amputations and 10 cases ot eleven incomplete amputations survived. A total of 22.5 cases(86.5%) of replanted limbs and digits survived. 6. The results of joint motion, two point discrimination, sensory recovery and status of sweating due to recovery ot sympathetic nervous function following replantation were satisfactory. 7. In the early stage of our series, postoperative systemic heparinization was used in some cases, but recently we have achieved good recults without it. 8. Main causes of reattachment failure were tissue crushing and secondary thrombosis of the anstomosed vessels.