The type of flat foot that we have called pes valgus with plantar flexed talus, flexible, was treated in children with the Helfet heel seat or the UCBL shoe insert. In follow-up examination of 71 cases for periods longer than one year, 79 per cent of the patients showed that the UCBL shoe insert and the Helfet heel seat improved the clinical and roentgenographic appearance of the foot. The Helfet heel seat is recommended in cases where the plantar flexion angle of the talus is 35 to 45 degrees and the UCBL shoe insert in those cases of plantar flexion of the talus greater than 45 degrees.