Cubitus varus deformity following mal-union of a supracondylar fracture of the humerus in children causes no functional disability, but surgical correction is often requested to improve the appearance of the arm. Maintaining the correction after supracondylar osteotomy is a difficult aspect of the operative treatment and remains controversial. Nine children aged between 6 and 12 years (average 8 years and 11 months) underwent lateral closing wedge supracondylar osteotomy of the humerus, for deformity ranging between 10 and 20 degrees (average 13 degrees). The correction required ranged between 16 and 30 degrees (average 21 degrees). The osteotomy was internally fixed with a two hole marrow plate. At follow-up, which ranged between 3 months and 6 years (average 34 months), six patients were graded as good, two as satisfactory and one as a poor result. One patient had transient radial nerve palsy which recovered completely in 2 months. The patient who was graded poor had undercorrection of the deformity at the original operation. There was no incidence of loss of correction due to implant failure. Complete section of the bone to allow medial displacement of the distal fragment is recommended, thereby avoiding lateral bony prominence at the elbow.