Real-time ultrasonography is a simple. accurate, noninvasive and potentially valuable means of studying gallbladder size and emptying. The authors calculated ultrasonographically the ejection fraction of 80 cases of normally functioning gallbladder on oral cholecystography, from June 1983 to April 1984, at the department of ardiology. Hangang Sacred Heart Hospital. The results were obtained as follows; 1. Ultrasonographic Ejection Fraction at 30 minutes after the fatty meal was 73.1$pm$16.85 2. There was no significant difference in age and sex, statistically.