The recognition and elimination of dental compensation is essential in presurgical orthodontic treatment to achieve successful stabilization of the occlusion after surgery. However, the relationship between a transverse dental anomaly and skeletal asymmetry is not fully understood. To evaluate this relationship, frontal cephalometric and 3-dimensional dental model analyses were carried out on 44 adult Japanese Class III patients (mean age 21 years 11 months) who required surgical orthodontic treatment. The patients were divided into 2 groups: a facial asymmetry group in which the mandibular transverse deviation exceeded +/- 1 SD from the norm, and a control group in which the mandibular transverse deviation was within +/- 1 SD of the norm. Statistical comparison with a control group showed characteristic dental anomalies in the facial asymmetry group, including asymmetry of the curve of Spee, molar inclination, dental arch form, lateral overjet, and slanting of the occlusal plane. Stepwise linear regression analysis showed that transverse and vertical skeletal asymmetry variables including the mandible and the maxilla were effective parameters for characteristic dental anomaly variables, and a significant high correlation between dental anomalies and skeletal asymmetry was found.