Though the problem is yet under discussion whether the rachitis of infants may occur congenitally or not, the general tendency of clinicians can be said to deny its congenital existense, considering it at any rate a very rare or even exceptional case. To the contrary a X-ray examination of the newly born infants has revealed such changes of long bones, especially markedly at the distal ends of ulna, as those in the rachitis of children. In order to study these X-ray vague chadows and investigate their etiology, the authors wanted to take into consideration the living conditions of the mother, with especial reference to health, food, living place and environments etcthe factors regarded to be in close connection to the rachitis etiology. The number of cases treated amounted to 70. The results of investigation revealed that a co-relation was existing to a certain extent between the X-ray changes and weak constitution, bad nutrition, poor food, ill environments, poor life which were deficient in sunshine, bodily exercise etc. These relations correspond roughly to the communications, which are believed to be etiological factors of the rachitis of children.