Giant cell tumor of tendon sheath is a slow-growing, unilateral and solitary lesion that is most commonly seen in the digits of the hand and knee, but occasionally occurs in the hips, ankles, toes and wrists. The lesion is asymptomatic or mildly painful, especially if it is diffuse and located in a major joint. The concepts concerning about the pathogenesis of these lesion have undergone constant revision, which include neoplastic process, inflammation and lipid metabolism. Authors analysized 20 patients with giant cell tumor of tendon sheath about the etiology, clinical findings, pathologic findings and treatment results. The results were as follows: 1. 13 cases were females (65%) and 7 cases were males (35%), and the range of age was from 9 years old to 60 years old. 2. The hand was most frequently involved site in which 14 cases (70%) were included, and the foot was involved in 5 cases (25%). 3. Solitary lesions were 15 cases and multiple lesions were 5 cases. 4. Radiographically, in 3 cases bony erosion was seen. 5. All cases were treated by surgical excision and presented no recurrence. In conclusion, the giant cell tumor of tendon sheath, which has been considered to be benign tumorous conditions appeared to be necessary for complete surgical excision to prevent recurrence.