Results of the operative treatment of phosphate-diabetes are presented on the basis of our own patients. Deformations of the lower extremities need in case of a disturbed function and disfigurement of the gait picture a surgical correction, by which we should strive as much as possible for physiological axial proportions in both planes. For young children osteoclasis with fixation in plaster cast will suffice, for adolescents and grown-ups we prefer stable osteosynthesis. An adequate straightening, combined with a regular control of the mineral metabolism and an appropriate drug therapy, guarantee good long-term results and absence of recidivity.