The authors analysed the 87 patients of the lateral condyle fracture of the humerus in children who were admitted in 4 hospitals in Pusan from Jan. 1987 to Dec. 1991. The fracture type and the displacement was classified according to Milch type, Jakob stage and Badelon classification. We could follow up 57 cases and analysed which factors affected the development of complications. The patients were followed up from one year to five years and four months with an average of 27 months. The results were as follows; I. Age 1. The age distribution was confined from age of one year three months to eleven years three months. 2. The younger the patient was, the more severe the fracture displacement was and the older the patient was, the milder the fracture displacement was. II Classification l. According to Milch type, type I was 13 cases (14.9%), type II, 74 cases (85.1%). According to Jakob stage, stage I was 14cases (13.8%), stage II, 47 cases (54.1%) and stage III, 28 cases (32.1%) 2. According to Badelons classification, 2 cases (12.3%) were type I, 15 cases (17.2%) type II, 42 cases (48.4%) type III and 28 cases (32.1%) type IV. III. Complications 1. The complications were 18 cases of angular deformity, 14 cases of bony spur, 6 cases of capitellar enlargement, 12 cases of premature epiphyseal fusion, 4 cases of avascular necrosis. 2. It seemed that there was no correlation between fracture type or degree of displacement and change of the carrying angle. 3. Bony spur (14/57) was developed after open reduction in all cases and it seemed that it was caused by operative procedure (malreduction, periosteal elevation) 4. In capitellar enlargement (6/57), all cases were severely displaced type III or IV of Badelon classification. 5. In premature epiphyseal fusion, Milch type I (4/9) was more common than Milch type II(8/48), and the number of pin penetration of the capitellum during fixation was major factor. 6. We thought that the severity of initial trauma, delayed open reduction with extensive soft tissue dissection and damage of capitellum during multiple pin fixation wers important causing factors of avascular necrosis.