PURPOSE: The purpose of this study was to assess the clinical interventions and the accuracy of maxillary reposition using a computer-aided design/computer-aided manufacturing (CAD/CAM) splint derived via surgical simulation. MATERIALS AND METHODS: The retrospective study comprised 24 patients who underwent bimaxillary surgery. The patients were assigned to 1 of 2 groups by a way of maxillary repositioning. One group received conventional intermediate wafers and the other CAD/CAM wafers during Le Fort I osteotomy. We recorded operation time, blood loss, the operative accuracy. Accuracy was analyzed by 3-dimensional computed tomography images before and immediately after the operation. The evaluation points were the right maxillary first incisor (U1), the right maxillary second molar (M2-right), and the left maxillary second molar (M2-left). RESULTS: The 2 groups did not differ significantly in operation time and blood losses. The vertical axis of U1 data differed significantly between the 2 groups (P = 0.008). None of the horizontal, vertical, or anteroposterior axis of M2-right data differed significantly, and anteroposterior axis of M2-left data differed significantly (P = 0.0296). The CAD/CAM group 3-dimensional distance errors were less than those of the conventional group for all points. CONCLUSION: Placement of CAD/CAM splint allowed highly accurate repositioning; the accuracy exceeded that afforded by conventional model surgery using a facebow and articulator.