The purpose of the present study was to compare the clinical and radiographic results between 2 procedures, lateral opening wedge calcaneal osteotomy (LCL) and medial calcaneal sliding-opening wedge cuboid-closing wedge cuneiform osteotomy (3C) in patients with planovalgus foot deformity. A total of 38 patients who underwent either LCL (18 patients, 28 feet) or 3C (20 patients, 32 feet) were included in the present study. The etiology of the planovalgus foot deformity was idiopathic in 16 feet and cerebral palsy in 44 feet. The 2 procedures used in the present study were indicated in symptomatic (pain or callus) children in whom conservative treatment, such as shoe modifications or orthotics, had been applied for more than 1 year but had failed. The patients were evaluated preoperatively, postoperatively, and at the last follow-up visit, both clinically and radiologically, and the interval to union and postoperative courses were compared between the 2 groups. In the LCL group, 19 of the 28 feet (68%) showed a satisfactory outcome and 9 (32%) an unsatisfactory outcome. In the 3C group, 28 of the 32 feet (88%) showed a satisfactory outcome and 4 (12%) an unsatisfactory outcome. The clinical results were not significantly different between the 2 groups, with mild to moderate pes planovalgus deformity. However, the clinical results were better in the 3C group with severe pes planovalgus deformity than in the LCL group with severe pes planovalgus deformity. All 4 radiographic parameters were improved at the last follow-up visit in both groups. In particular, the talar–first metatarsal angle and the calcaneal pitch angle on the weightbearing lateral radiographs were significantly improved in the 3C group with mild to moderate planovalgus foot deformity. All 4 parameters were significantly improved in the 3C group with severe planovalgus foot deformity. No significant differences were observed between the 2 groups in terms of the interval to union and postoperative care. No case of postoperative deep infection or nonunion was encountered in either group. 3C is a more effective procedure than LCL for the correction of pes planovalgus deformity in children, especially severe pes planovalgus deformities.