Leukemia is the commonest malignancy in childhood, accounting for about one-third of all malignancies in those below th eage of 15 years. Authors analysed the chest PA findings of 177 cases of leukemia in childhood below the age of 15 years, diagnosed at Seoul National University Hospital in recent 5 years since 1978. The Summaries of the analysis are as follows : 1. Among 177 cases, 121 cases were male and 56 cases were female. The male predominant than the female with the ratio of 2.2 : 1. In 177 cases, 77% of the patients were under the 10 year of age. 2. The incidence of subtype of leukemia was as follows : The acute form was 158 cases (89%), acute lymphocytic leukemia, 55% acute myeloctic group, 31.6%, chronic myeloytic type, 10%. And acute lymphocytic leukemia was 61.4% of acute form. 3. The incidence of abnormality in chest PA was 32.2% (57 cases). Among these 57 cases, abnormality I lung field was 35 cases (19.8% of total patients) hilar and mediastinal lymph nodes enlargement was 19 cases (10.7%). Pleural effusion was 13 cases (7.3%) and cardiac shadow enlargement in chest PA was 3 cases.