Objective: To evaluate the operational mastication function on occlusion of post operative patients suffered Le Fort I, Le Fort II and Zygomatic Arch Fractures. Material and methods: Prospective observational study describing operational occlusion on patients suffered from Lefort I, II and zygomatic arch fractures, describing the movement of the mandibular in correlation with the upper face in implementation of physiological function. Results: Fifty five patients including 50 males (90.9 percent) and 5 females (9.1 percent), median age 28.0 +/- 9.02 (17-54) suffered from Le Fort I, II with or without zygomatic arch fractures, were reviewed 6 months after surgery. Regarding the operational mastication function on occlusion, control results showed that 78.2 percent patients having amplitude of maximal mouth opening of more than 40mm, 76.4 percent patients having amplitude of right side shift more than tmm and 78.2 percent patients having amplitude of left side shift more than 7mm. 76.4 percent having easy lateral movement, 16.4 percent having working side interference, 3.6 percent nonworking side interference. 60 percent having amplitude of protrusive movement 46mm, 80 percent having easy protrusive movement, 43.6 percent having straight protrusive movement, 36.4 percent edge to edge contact of 4 teeth in protrusive movement. 21.8 percent having protrusive movement. Conclusion: Almost of patients in research group of post operative of upper facial fractures and zygomatic arch fractures have quite good outcomes of mastication function.