This study aimed to compare chin deviation in angle measurement on posteroanterior(PA) cephalogram and computed tomography (CT). Chin deviation was assessed as menton(Me) deviation in angle measurement on PA cephalogram and CT images of 35 patients who had orthognathic surgery (19 male and 16 female with average age of 22.1±3.33yr). The difference between the Me deviation was calculated and statistical analysis was performed to compare the deviation direction and asymmetry severity on the two imaging modalities. There was statistically significant difference in the difference of Me deviation between PA cephalogram and CT by one-simple t -test ( p <.05). The mean difference of Me deviation was 2.21°± 1.84°. The maximum difference of Me deviation was 8.64°. There were statistical agreements in the deviation direction (k =0.82, p <.05) and in the severity of facial asymmetry (k =0.37, p <.05). The difference of the deviation direction was detected in 2 patients (5.71 %). The difference of the severity of facial asymmetry was in 15 patien