The purpose of this study is to obtain the enshortening and elongation rate of image in orthopantomograph. The subjects were consisted of 15 dry skulls attached with radiopaque materials on each anatomical points. The length measurements were performed between two points on dry skull, and between two points on film. The results are as follows: 1. The enshortening and elongation rate between two anatomical points (1) ANS↔infraorbital foramen (left:+1.3%, right:+0.7%) (2) ANS↔maxillary tuberosity(left:-11.7%, right:-14.3%) (3) Zygomatic arch length(left:-4.8%, right:-8.9%) (4) first molar↔infraorbital foramen (left:+19.8%, right:+24%) (5) inter-infraorbital foramen length(-21.4%) (6) inter-first molar length (-31.8%) (7) inter-mental foramen length(+1.4%) (8) mental foramen↔mandible angle (left:+3.3%, right:+3.3%) (9) mental foramen↔lingula(left:+8.2%, right:+3.3%) (10) mental foramen↔condyle head(left:+5.2%, right:+4.5%) (11) mandible↔condyle head (left:+15.4%, right:+16.4%) 2. The closer the object is to the occlusal plane and the median line, the smaller it appears.