To describe the technique, analyze possible radiographic correction and evaluate the clinical result of medial and plantar calcaneal displacement osteotomy associated with opening wedge cuboid osteotomy for flexible flatfoot correction. 23 patients (30 feet) diagnosed with flexible flat foot treated with plantar and medial calcaneal displacement osteotomy associated with opening wedge cuboid osteotomy were evaluated retrospectively. In the lateral radiographs calcaneal pitch and Meary's angle were the radiographic parameters evaluated; while the talonavicular coverage angle was evaluated in the anteroposterior radiographs. To assess the clinical outcome of the surgical procedure, the American Orthopedic Foot and Ankle Society Score (AOFAS) for the ankle and hindfoot was adopted. The mean values of the evaluated angles and AOFAS score for ankle and hindfoot significantly improved when comparing pre- and postoperative values. Plantar and medial calcaneal displacement osteotomy associated with an opening wedge cuboid osteotomy is able to improve radiological and clinical parameters of child patients with flexible flatfoot.