PURPOSE: The purpose of this study is to compare the diagnostic accuracy and usefelness of three dimensional CT, plain radiography and two-dimensional axial CT in cases of maxillofacial fracture. MATERIALS AND METHODS: Plain radiography, two dimensional axial CT, and three dimensional helical CT images of eighty-two maxillofacial fractures in 45 patients were retrospectively analyzed according to detectability of fracture and displacement. The diagnostic accuracy of each modality was analysed using the Ridit method. RESULTS: Two- and three-dimensional CT were superior to plain radiography in evaluating fracture and displacement (p=0.001, 0.039), though the type of CT used did not cause significantly variation in the accuracy with which fracture and diferrent were diagnosed. CONCLUSION: Three dimensional helical CT is useful not only in the detection of fracture but in the evaluation of displaced maxillofacial fractures, especially if these are multiple and the complex.