The authors reviewed 49 cases(48 patients) of benign bone tumor who had surgical treatment with xenograft at department of orthopedic surgery, Seoul National University Hospital from May, 1980 to May, 1994. Materials consist of 21 males and 27 females. The mean age at operation was 20.1 years(range : 4 -55 years) and the mean follow up period was 25.4 months(range : 7 - 85 months). We did xenograft only in 34 cases and xenograft mixed with autograft in 15 cases(14 cases, from ilium, 1 case from femur). The used materials for xenograft were $Lubboc^{(R)}$ in 29 cases, $Surgibone^{(R)}$ in 17 cases and $Pyrost^{(R)}$ in 3 cases. The average durations when bony union was achieved in radiograph were 13.8 weeks in whole cases, 12.5 weeks(range : 8 - 24 weeks) in $Lubboc^{(R)}$ graft cases and 15.7 weeks(range : 6 - 24 weeks) in $Surgibone^{(R)}$ graft cases. The tumor recurred in 4 cases, 1 case was recurred giant cell tumor at distal femur treated with mixed auto and $Lubboc^{(R)}$ graft and 2 cases were large cystic lesions at the proximal humerus diagnosed as simple bone cyst and at distal tibia diagnosed as fibrous dysplasia treated with $Surgibone^{(R)}$ graft and 1 case was aneurysmal bone cyst of the proximal tibia treated with $Lubboc^{(R)}$ graft. Wound infection occurred in 1 case. More transfusion was done in the cases that the lesion was larger than 5cm, the lesions were in the ilium or femur and the cases that were treated with mixed with autograft. This study implies that benign bone tumor is successfully treqated with curettage and xenograft or xenograft mixed with autograft. And also this method will reduce morbidity of donor site, intraoperative bleeding and post-transfusion complications.