In the treatment of valgus flat foot in adolescent patients, when growth has nearly ceased (about 13 years in the female and 15 in the male) the operation of choice is varus osteotomy of the calcaneum, stabilised by a homoplastic bone wedge, together with tenodesis of tibialis anterior and posterior. At this age, skeletal growth is not sufficient to guarantee corrective evolution of the deformity after repositioning of the calcaneo-talar joint by any surgical technique. Varising osteotomy of the calcaneum offers the advantage of avoiding sacrifice of the calcaneo-talar joint, as in the Grice-Green arthrodesis, which although indicated for the paralytic valgus flat foot, is not appropriate in the idiopathic variety.