PURPOSE: While normal ultrasound measurement of the gallbladder (GB) is well established in adults, little attention has been focused on the normal measurement of the pediatric gallbladder. Normal parameters of the pediatric gallbladder may be significant to establish disease criteria, because some gallbladder diseases are only accompanied by changes in gallbladder size. We therefore wish to document the normal ultrasonic parameters of the pediatric gallbladder. MATERIAL AND METHOD: Five hundred and ten children with normal clinical findings andlaboratory data were included in this study. Ultrasonography was performed as a part of a health screening examination from the Dec. 1994 to Feb. 1995. Sonographic parameters included gallbladder size, volume, and clinical parameters such as age, height, weight, and body surface area were noted stastical significance between the sonographic and clinical parameters was analyzed through correlation and regression analysis. RESULTS: The patient age was ranged from 0 to 16 years, and the male : female ratio was 1.5 : 1. The longitudinal length of GB showed significant positive correlation with patient age(0.504), height(r=0.527), body weight(r=0.492), and bodsurface(r=0.522)(p <0.0001). The result of correlation analysis and regression analysis to the volume of gallbladder was also significant(r : 0.403-0.515, p <0.0001). The correlation analysis to the transverse length of gallbladder shows relatively low correlation coefficiency(r=0.290-0.398), however, the result of regresion analysis shows significance(p <0.0001). The range of mean value of gallbladder size according to age was 3.32(+/-0.73)-6.81(+/-1.05)cm in longitudinal length, 1.10(+/-0.37)-2.01(+/- 0.57)cm in transverse length, and2.46(+/-1.66)-15.35(+/-8.18)cm3 in volume. CONCLUSION: The mean values of pediatric gallbladder may be an useful index for the clinical application to vanior gallbladder disease.