Aims: To evaluate the effect of Le Fort I osteotomy on nasal form and function. Method: Twenty-five patients undergoing Le Fort I osteotomy for anterior, anterior/superior and anterior/inferior maxillary repositioning were prospectively studied for changes in nasal form and function. Seventeen patients underwent bimaxillary osteotomy. They were evaluated before and 6 months after Le Fort I osteotomy. The nasal form was determined by measurement of standardized raster photographs of the nose and lateral teleradiography. The distances and angles of the nasal base were determined. The nasal profile was assessed by measurement of the nasofacial angle (NF), the nasolabial angle (NL), the angle between upper lip and Frankfort horizontal plane (L/FH), the angle between columella and FH (N/FH) and the nasocolumellar angle (NC). Nasal function was evaluated by anterior rhinomanometry, whereby the overall flow (ccm/s) was determined. Results: The results were classified in groups according to the different repositioning. The distances and the angles of the nasal base were significantly increased in all groups. As for the nasal profile, there was no significant increase of NL, L/FH, N/FH and NC in all groups but significant increase of NF (p Keywords: Le Fort I osteotomy, nasal form, nasal function, rhinomanometry