Purpose: To evaluate the osseous changes of TMJ in internal derangement and osteoarthritis patients using MRI. Materials and Methods: MR images of 111 TMJs in 64 patients were analyzed to evaluate the osseous changes, 111 TMJs were divided into 6 groups according to the radiologic Stages by Schellhas and Wilkes. On MR images, we evaluate the osseous changes of articular eminence and condylar head. Results: The most frequent Stage in internal derangement of TMJ was Stage I. And 28 joints (25.2%) revealed osteoarthritis with internal derangement. When osseous change of articular eminence and condylar head occur, flattening was the most common osseous change. Sclerosis was observed in all Stages and osteophytosis of condylar head was observed in Stage II (1.8%) and III (0.9%). Out of 28 joints with osteoarthritis, 6 joints (21.4%) showed joint effusion. Conclusion: MR image revealed abnormal configuration of disk, but the detection of minimal osseous change was subtle.