Hypertrophic pyloric stenosis of infant is relatively common disease, the roentgenologic examination givesunequivocal and reliable information than other diagnostic procedures in diagnosing this disease. Total 19 casesof hypertrophic pyloric stenosis, admitted at Dong-San presbyterian hospital during 1969 to 1977, studied by meansof roentgenologic findings. 16 of 19 had roentgenological examination. The results are as follows. 1. 84.2% aremale. 2. Between 1 month to 6 months of age are 11 cases, about 58%. 3. Roentgenologic findings are String sing11(68.7%), Beaked sing 10(62.5%), Tit 5, Shoulder 5(each 31.3%) and Mushroom 2(12.5%), Delayed emptying were 7cases (43.8%).