Le Fort I osteotomies frequently involve impaction of the maxilla into the nasal cavity, potentially affecting nasal form. It has been speculated that a concomitant change in nasal function may occur. The purpose of this study was to determine if there is an association between maxillary position and nasal function and to evaluate the influence of Le Fort I surgery on nasal function. Presurgical and postsurgical nasal resistance and percent nasal respiration were compared in 36 patients. Results indicated a mean change in nasal resistance 1 year after surgery, but mean percent nasal respiration did not change significantly. No prediction could be made for any patient relative to the effect of maxillary surgery on the nasal function parameters. No consistent association could be found between the amount or direction of maxillary surgical movement or the position of the maxilla and nasal respiration.