This study was conducted to assess the usefulness and limitations of high-resolution CT for diagnosing the ossicular chain in the middle ear. The CT images in this study were obtained in as much detail as possible and 2 direction images. Preoperative CT findings of the ossicular chain were compared with operative findings in 26 patients with ossicular defects. Preoperative detection of the complete defect of the malleus head and the body and long process of the incus by high-resolution CT was possible in all cases, while detection of the defect of the manubrium of the malleus and superstructure of the stapes could be made in 33.3 and 60%, respectively. The defect of the incudostapedial joint (1 case) and partial defect of the stapes cms (2 cases) could not be diagnosed correctly by preoperative estimation.