The orthognathic surgery is the procedure to correct dentofacial deformities. Today the Virtual Surgical Planning (VSP) is the best tool to visualize the possible maxillomandibular final position. One of the most asked questions is: since the mandible is a mobile bone, the VSP can be predictable for the final result of the positioning of the mandible? Then a retrospective and observational study was developed to find the VSP predictability in mandibular movements after orthognathic surgery. Were research in class II and III patients using Composite Skull (Computed Tomography CT associated with dental scan). Linear and angular measurements were done comparing VSP to postoperative CT, with at least 6 months after surgery. Eight patients were included in the study. The cephalometric analysis was done using the Proplan software (Materialise Proplan CMF, São Paulo, Brazil). The results of the simulated in VSP and real movements of mandibular points were compared, calculating their linear and angular differences. A total of fourteen measurements were done and evaluated through of the t test, Bland-Altman, Wilcoxon and the Dahlberg error. In addition to being evaluated by clinically acceptable bias (+/- 2 mm). In the total, 4 differences were statistically significant (Chin height, HFP/Me, HFP/LLM, Coronal/Pg, FMA angle). The mean bias in linear measurements ranged from -3.23 mm (Coronal Plane/Pg) to 3.71 mm (PHF/Me). The VSP seems to be a precise and reproducible method as a way of elaborating treatments, reliably transferred to the patient through surgical guides. Although the 4 differences were statistically significant, when clinical measurements compared with them, only 2 measurements (HFP/Me and Coronal/Pg) result in a clinical significantly difference, 25% and 50%, respectively, result that can be explained by the absence of genioplasty guides.