The results of femoral lengthening using the Italian modification of the Ilizarov are presented. Mean age of the patients was 14 years (ranging from 7 to 29). The most frequent etiology of limb shortening was femoral hypoplasia (7 patients) and sequelae of septic arthritis of the hip and/or the knee (6 patients). Indications for surgical treatment were limb shortening from 3 to 12 cm (mean 6.5 cm), along with axial deviation ranging from 10 degrees to 40 degrees in 6 patients. Mean follow-up time was 15 months (ranging from 6 to 35 months). The Ilizarov apparatus was based on two distal rings, stabilized by "K" wires, and proximally by a ring connected with an Italian femoral arch, stabilized by a Schanz screw. Planned lengthening (ranging from 3.5 cm to 12 cm) was achieved in all treated patients. The healing index ranged from 0.8 to 2.1 month/cm (mean 1.4). Problems, obstacles and complications were analyzed according to the Paley classification. In all 16 patients without primary knee stabilization, limited knee flexion ranging from 5 degrees to 90 degrees (mean 40 degrees) was noted during the distraction phase, which didn't improve significantly during the consolidation phase. Knee flexion improved to a mean 90 degrees after a 6 month follow-up. Bone regenerate defects (cysts, narrowing) were noted in 4 patients. Secondary knee stabilization was performed in 2 cases. In the first case because of knee pain and a severe limitation of knee motion. In the second, during a revision procedure because of distal femur angulation. Premature consolidation was noted in one patient and was treated by osteotomy. In one case axial deviation during the consolidation phase required osteotomy. In another case a fracture of the femur was treated by a plaster cast. In one case 1.5 years after the lengthening procedure subluxation of the hip was noted. Permanent knee flexion limitation to less than 90 degrees was noted in 6 patients. Femoral lengthening with the use of the Italian modification of the Ilizarov device give a high incidence of knee range of motion limitation, which can be decreased by preserving more than 30 degrees knee flexion during the distraction phase.