Vertical asymmetry of the maxilla can determine the inclination of the occlusal plane and result in a lack of internal reference points usually employed to measure surgical movements. Maxillary repositioning is therefore based upon surgical planning, which is commonly elaborated on dental casts and model surgery. The absolute precision of surgical planning is not guaranteed by dental casts and model surgery, and the intraoperative assessment of maxillary repositioning is considered to be of paramount importance in such cases. This article describes a simple, noninvasive intraoperative technique that is useful in measuring the vertical dimension of the maxilla and helps to indicate precise repositioning. It illustrates the technique and reports the results obtained in a series of 30 patients treated surgically for maxillomandibular malformations with vertical asymmetries and occlusal plane inclination from January to December 2000 at the Maxillofacial Surgery Department of La Sapienza University in Rome, Italy. (Int J Adult Orthod Orthognath Surg 2002;17:111–115)