From January 1985 to February 1997, 96 patients had undergone the free vascularized groin flap on the upper and lower extremities with microsurgical technique at the department of orthopaedic surgery, Yonsei University College of Medicine. The results were as follows: 1. Average age at the time of operation was 24.9 years. and there were 71 men and 25 women and mean follow up was 62.4 months. 2. The lesion site was 82 cases on the lower extremity: foot(40), leg(20), ankle(13), and 14 cases on the upper extremity: forearm(6), elbow(3), hand(3), wrist(2). 3. The anatomical classification of the superficial circumflex iliac artery was as follows: 1) 39.8% of common origin with superficial inferior epigastric artery, 2) 30.1% of isolated origin and absent superficial inferior epigastric artery, 3) 13.3% of separate origin, 4) 16.9% of origin from the deep femoral artery. 4. There was no statistical significance on arterial anastomosis between end to end and end to side, and on venous anastomosis(end to end) between one vein and two veins. 5. The success rate was average 84.4% in 81 of 96 cases. 6. In the 15 failed cases, the additional procedures were performed: 5 cases of free vascularized scapular flap, 6 cases of full thickness skin graft, 2 cases of cross leg flap, 1 case of latissimus dorsi flap, 1 case of split thickness skin graft. In conclusion, the free vascularized groin flap can be considered as the treatment of choice for the reconstruction of the extensive soft tissue injury on the extremities, and show the higher success rate with the experienced surgeon.