PURPOSE: We tried to compare the clinical and the radiologic features between the extension and the flexion type of supracondylar fractures of the humerus in children. MATERIAL AND METHODS: Between May 1995 to September 1999, 68 extension type and 7 flexion type fractures were treated surgically. Baumann's angle, humeroulnar angle, carrying angle, clinical result and clinical features were analyzed and the flexion types were compared with the extension types. Changes in Baumann's angle, humeroulnar angle and carrying angle were evaluated as Excellent or Good, Fair, Poor with reference to the opposite elbow by Kallio method. The Clinical results were evaluated as Excellent or Good, Fair, Poor by the modifying Kallio method. RESULTS: Mean changes in Baumann's angle were 4.6degrees , 9.3degrees and those in the humeroulnar angle were 3.8degrees , 8.0degrees ( respectively in extension and flexion type (P=0.047, P=0.021, respectively). Changes in carrying angle were Excellent or Good( <10degrees ), Fair(10 ~15degrees ), Poor(≥15degrees ) in 65, 1, 2 children in extension type and 3, 4, 0 children in flexion type, respectively. Clinical results were Excellent or Good, Fair, Poor in 59, 6, 3 children in extension type and 3, 4, 0 children in flexion type, respectively (P=0.002). CONCLUSION: Changes of Baumann's angle and carrying angle in flexion type of supracondylar fractures of the humerus in children were greater than those in extension type. The clinical results were poorer in flexion type. We suggested that treatment for flexion type supracondylar fractures should be careful and meticulous with frequent radiologic checkups and follow-ups. Also, if a reduction is not satisfactory with closed method, open reduction should not be hesitated.