Purpose : While normal ultrasound measurement of the gallbladder (GB) is well established in adults, littleattention has been focused on the normal measurement of the pediatric gallbladder. Normal parameters of thepediatric gallbladder may be significant to establish disease criteria, because some gallbladder diseases are onlyaccompanied by changes in gallbladder size. We therefore wish to document the normal ultrasonic parameters of thepediatric 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 screeningexamination from the Dec. 1994 to Feb. 1995. Sonographic parameters included gallbladder size, volume, andclinical parameters such as age, height, weight, and body surface area were noted stastical significance betweenthe sonographic and clinical parameters was analyzed through correlation and regression analysis. Results : Thepatient age was ranged from 0 to 16 years, and the male : female ratio was 1.5 : 1. The longitudinal length of GBshowed 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 ofgallbladder was also significant(r : 0.403-0.515, p〈0.0001). The correlation analysis to the transverse length ofgallbladder shows relatively low correlation coefficiency(r=0.290-0.398), however, the result of regresionanalysis shows significance(p〈0.0001). The range of mean value of gallbladder size according to age was3.32($pm$0.73)-6.81($pm$1.05)cm in longitudinal length, 1.10($pm$0.37)-2.01($pm$ 0.57)cm in transverse length, and2.46($pm$1.66)-15.35($pm$8.18)cm3 in volume. Conclusion : The mean values of pediatric gallbladder may be an usefulindex for the clinical application to vanior gallbladder disease.