The purpose of this study was to analyze the positions of upper and lower incisors according to facio skeletal patterns. The lateral cephalometric radiographs of sixty persons with normal occlusion, forty persons with Class II Division 1 malocclusion, and forty persons with Class III malocclusion all above the age of 18, were analyzed. The following results were obtained. 1. C I angle, the measurement related to masticatory system, were 89.20 ± 4.34° in normal occlusion group, 81.68 ± 5.95° in Class II Division 1 malocclusion group and 101.96 ± 6.31° in Class III malocclusion group. 2. In comparison with the positions of upper and lower incisors according to facioskeletal patterns, Class II Division 1 malocclusion group showed that upper incisors were different significantly in all measurements and inclined labially (P< 0.05). Lower incisors were different significantly in all measurements except LI-APog, LI-APog (mm), LI-AB, LI-AB (mm) and inclined labially (P< 0.05), Class III malocclusion group showed that upper incisors were different significantly in all measurements except UI-SN, UI-OP, and inclined labially (P< 0.05). Lower incisors were different significantly in all measurements and inclined lingually (P<0.05). 3. In all facioskeletal patterns, LI-SN and LI-PH ware correlated moderately to facioskeletal measurements, and FMA was correlated moderately to measurements of lower incisor position. 4. Regardless of the facioskeletal patterns, the reference planes equally applicable were AB line in the measurements of upper incisor and APog line in the measurements of lower incisor.