The aim of this study was to establish the diagnostic criteria of normal submandibular glands in adults. Materials included 132 sialograms of selected person from 23 to 28 years of age. In subjects each variable was measured and evaluated statistically introducing 18 items respectively. Conclusions from this study were as follows. 1. The mean diameter of main duct was 1.96㎜ in distal end and 2.71㎜ in hilar end, so the diameter of distal end was smaller than that of hilar end in submandibular glands. 2. The mean length of main duct was 42.02㎜ in submandibular glands. 3. The mean angle of main duct was 35.67 degrees with inferior border of mandible and 103.05 degrees at posterior mylohyoid portion. 4. In configurations following shape of main duct, those revealed that 39.39% of cases of the curvilinear type, 16.67% of cases of the linear type, 22.73% of cases of the sigmiod type and 21.21% of cases of the angular type. And in configurations following course of main duct, those revealed that 83.33% of cases of the smooth type and 16.67% of cases of the tortuous type. 5. The mean caliber of submandibular glands was 45.59㎜ in superoinferior height, 43.56㎜ in anteroposterior width, 28.85㎜ in mediolateral width and 33.65㎜ in extent below mandibular angle. 6. Well-delineated acinar parenchyme was observed in 77.28% of cases and well-defined tertiary ducts in 50.06% of cases. 7. There were no differences between right and left submandibular glands in size and shape of main duct and parenchymal portion, but there were great variations in each individual.