Thirteen Polio patients with leg length inequality were undergone Ilizarov lengthening procedures and have been followed along for an average two years(range, 1-3.8 years) after removal of the fixator. The age of patients(M:F=7:6) ranged from 18.0 to 32.2 years(average 26.4 years). The difference of true leg length averaged 2.1cm with the tibia being 3.3cm the femur, 1.2cm. The corticotomy was done at the proximal tibia and distal fibula in all case. The fixation period of the Ilizarov apparatus averaged 9.3 months. The length gain averaged 3.0cm for an average 3.8cm inequality. The healing index averaged 3.1mon/cm. Two out of thirteen patients complained of pain in the operated leg. The limping gait was improved in all patients except one. According to Paley's classification, there were ten cases of problems, one obstacle and four true complications. The problems were pin site infection controled with local antibiotics injection. There was one case of obstacle; tibial valgus deformity developed during lengthening. True complications included peroneal nerve injury, aggravation of preexsiting equinovalgus and claw toe deformities, aggravation of preexsiting valgus deformity of ankle and tibial valgus deformity. The complications execpt in one case of peroneal nerve palsy were solved out by the secondary procedures. In summery, the bone healing by distraction osteogenesis with the Ilizarov technique was relatively delayed in polio patients and it seems necessary to modify the technique to shorten the prolonged external fixation period.