Four patients with congenital pseudarthrosis in neurofibromatosis were treated with percutaneous transosseous fixation according to the Ilizarov method. Three tibias were first treated unsuccessfully with a Sofield procedure. After application of the Ilizarov fixator, consolidation was obtained in two cases after 6 and 19 months, respectively. A fourth case consisted of a congenital pseudarthrosis of the ulna, primarily treated with the Ilizarov system, which showed advanced consolidation after 4 months.