Determination of the total lung capacity(TLC) has been widely used in the evaluation of the pulmonary function and in its application to clinical medicine. A roentgenographic method for the determination of the total lung capacity of Korean children of all ages has not yet been documented in the literature. This method requires posterioanterior and lateral views of the chest, and consists principally of the summation of a series of elliptical cylindroids into which the lungs are divided. The measurement and calculation of the total lung capacity by the roentgenographic method were carried out on 320 randomly selected normal Korean children, 180 males and 120 females. The following results were obtained: 1. The value of TLC in male was larger than that in female in the same age, height and weight group, the mean difference between male and female being 606 ml. The mean value of TLC in female was 77% of that in male. 2. TLC tended to increase as height increased, the correlation coefficients(r) being 0.86 with standard deviation of$pm$161 ml in male and $pm$562 ml in female, and it had an approximation to the value of 1Ht3 in male and 0.8Ht3 in female. 3. The TLD tended to increae slightly as weight increased, the correlation coefficient(r) being 0.78 with standard diviation of $pm$1061ml in male and $pm$738 ml in female. 4. Measurement of roentgenogram as regards TLC determination is relatively simple, rapid and accurate.