Neurofibromatosis type 1 (NF1) is the most common neurocutaneous disease. The clinical manifestations are diverse. Some of the skeletal changes are most relevant to the patient. We report on 9 patients with NF1 who presented with typical pseudarthrosis. In 8 of these children the lower extremity was involved. In 2 cases lesions of both tibia and fibula were found, in one case even over long segments with a fully instable leg. One child had a complete pseudarthrosis of the radius and ulna. This report analyses the bony changes, the operations performed and the possible technical improvements to be made. The present study as well as other recent studies suggest that bony lesions should be operated early using microsurgical methods.