AIM. This study aimed to clarify the relation between the angulation of the curved osteotome and fracture of the pterygoid plate during Le Fort I osteotomy. MATERIAL AND METHODS. Twenty-one specimens of hemisectioned Turkish skulls were used for the study. The maxilla was sectioned transversely on the floor of the pyriform aperture and posteriorly to the lateral pterygoid plate with a mechanical saw. The pterygomaxillary junction was separated with a curved osteotome by angulating the osteotome with, 0° and -30° to the occlusal plane. The undesired fractures of the lateral pterygoid plate were determined. Among 21 specimens, 7 pterygomaxillary junctions were separated with an angle of +30° , 7 with 0° and 7 with -30° to the occlusal plane. RESULTS. In group +30°, the undesired fracture occured in 6 of the cases. In group -30°, the undesired fracture was determines in one case. In cases where the separation was performed by placing the osteotome paralell to the occlusal plane all plates remained safe. CONCLUSION. Within the limited knowledge of the current study it can be concluded that the osteotome should be placed paralell to the occlusal plane.