It is essential to estiate the size, volume and wall thickness of the gallbladder diagnosis of the gallbladder disease. Author measured maximum length, A-P diameter, width, wall thickness and volume of gallbladder ultrasonographically in 130 normal adults. The results are as follows: 1. The mean length of the gallbladder was 5.88$pm$0.97 cm. 2. The mean A-P diameter of the gallbladder was 2.94$pm$0.52cm on longitudinal scan and 2.48$pm$0.42cm on coronal scan. 3. The mean width of the gallbladder was 2.48$pm$ 0.46cm. 4. The mean wall thickness of the gallbladder was 2.09$pm$0.29mm. 5. The mean volume of gallbladder was 27.09$pm$10.07$ extrm{cm}^2$ by single cylinder method and 18.27$pm$9.04㎤ by weill method, but there was linear correlation between the two methods (p<0.001)