We reviewed the cases of 10 patients with cubitus valgus deformity who had a supracondylar elbow fracture during childhood, in order to identify the causes of valgus deformity. Cubitus valgus deformity occurred in 3 cases because of failure to recognize the deformity at the initial treatment. In 7 patients the deformity was recognized but was insufficiently treated. In this series there was no evidence of progressive valgus deformity after healing of the fracture. Incomplete correction is the main cause of valgus deformity. It is suggested that, in order to reduce the incidence of valgus deformity following supracondylar elbow fracture, careful analysis of the fracture pattern is necessary and the initial angulation should be reduced anatomically and fixed in a correct manner.