Computed tomography has been advocated as an adjunct to conventional radiography in the evaluation of pelvic bone fractures and traumatic dislocations of the femoral head. Author compared and analysed the CT and plain radiographic findings of 3 consecutive adult patients in whom acetabular or femoral head injuries were suspected or demonstrated on initial radiographs. The result니 were as follows: 1. Computed tomography was conventient and precise mehtod in evaluating the patient with hip trauma. 2. Computed tomography was helpful in detecting intraaraticular osseous fragment, interposed soft tissue, and widening of the joint space which was not evident on plain radiographs. 3. Computed tomography permitted better evaluation of assciated injuries in soft tissue and viscera in the pelvic and retroperitoneal cavity, and also gave information about other associated fractures. 4. Computed tomography was superior for the evaluation of posterior acetabular rim and medial portion of the acetabulum. 5. Computed tomography was helpful for evaluating the pressence or absence of intraarticular osseous fragments after reduction of the dislocated hip.