Different open bite indicators have been described in scientificliterature. However, to attain proper and stable treatment it isimportant to be able to identify the etiology of the malocclusion.Facial patterns are directly related to growth direction, and thereforeto the vertical behavior of bone bases. They embody a crucialfactor for open bite expression. Description of facial pattern throughcephalometric measurements supplies information of affected bonestructures, providing thus an easier treatment. The aim of the presentstudy was, using Bimler facial formula, to identify bone structuresinvolved in open bite cases. Facial pattern was determined throughupper basal angle, lower basal angle and suborbital facial index.The study encompassed 40 lateral skull x-rays taken from patientsattending the Orthodontics clinic at the Graduate School, NationalSchool of Dentistry, National University of Mexico, within the 2004-2006 period. Patients had received diagnosis of skeletal open bite.This diagnosis was emitted with the help of open bite cephalometricindicators. Dominant facial pattern in skeletal open bite wasleptoprosopic. Six different relationships were found among upperand lower basal angles. Maximum open bite relation was 27.5% withboth jaws involved, followed by 40% (M/L) with less severity, 5%(L/L) with greater compensation, 5% (D/M) and m/ML with 2.5%.