The data are based on a study of 300 adult individuals of all ages between the 20-80 age groups chosen at random sample from Hanil Hospital from 1973 to 1977. Of these adult were asymptomatic with no apparent radiographic abnorm lity in stomach and duodenum. Over 3,000 measurements were made for this study also. The results were as follows; 1) Hypotonic type; The incidence of this type was 36.7% with high incidence in femele, especially in old individuals. The height of duodenal bulb is higher than other types. 2) Hypertonic type; The incidence of this type was 30.7% with same incidence I male and female. The maximal vertical internal diameter of du denal loop is longer than other types and minimal measurement of outer margin of 2nd portion of duodenum to posterior margin of vertebral bodies is shorter than other types. 3) J-Shaped type: The incidence of this type was 18% with same incidence in male and female the distance between pylorus and anterior margn of spine is longer than other types. 4) Casecade type; The incidence of this type was 14.6% with high incidence in male and not propotion with age. The maximal vertical internal diameter of diameter of duodenal loop is ihorter than other types and maximal horizontal internal diameter of duodenal loop is longer than other types.