PURPOSE: To describe the MR characteristics of giant cell tumor of bone. MATERIALS AND METHODS: MR iraagings of 15 cases of pathologically proved giant cell tumor were retrospectively analyzed. Signal intensity and homogeneity, involvement of articular surface, low signal intensity rim around the tumor, cortical disruption and soft tissue involvement were evaluated. RESULTS:Tumor showed low signal intensity on T1 weighted images(93%), inhomogenous high signal on T2 or T2* weighted images(93%) and inhomogeneous enhancing pattern(88%). In 11 cases of giant cell tumor of long bones, all cases showed involvement of articular margin and 10 cases(90%) showed rim of low signal intensity between tumor and normal marrow. Disruption of cortical bone(25%) and soft tissue involevement(7%) were also demonstrated. CONCLUSION: We concluded that giant cell tumor showed characteristic MR findings could be helpful in making correct diagnosis.