In patients with the sequele of poliomyelitis, pyogenic or tuberculous arthritis, or trauma, flexion contracture of the knee could be developed and many difficult problems would be met in treating them. Ilizarov suggested the method of gradual correction of deformities of bone after corticotomy-osteo- clasis, combined with gradual elongation of the shortened soft tissues, and the flexion contracture of knee & limb length discrepancy could be corrected simultaneously or sequentially following a sigle operative procedure. The authors have treated 25 patients with flexion contracture of the knee joint by the principle of Ilizarov treatment at the Sang Gye Paik Hospital between September 1991 and March 1994, The average preoperative flexion contracture of the knee joint, 25° (range, 10° -70° ) became 0° (range, flexion contracture 5° -genu recurvatum 5° ) afteroperation. The leg length discrepancy was projected to average 4cm(range, 2cm-10.5cm). Leg length equalization was achieved by one stage lengthening in 17 of 18 patients with an average 4cm(range, 2cm-10cm) lengthening. In one patient(case 12), there was 3cm residual shortening in tibia. Complications were encountered in 8 patients: flexion contracture of ipsilateral hip joint in 3 cases with severe knee flexion contrature, temporary knee stiffness in 6 cases, and stress fracture at the distraction site in 1 case. We found that Ilizarov method was effective to achieve lengthening and to correct deformities in flexion contracture of the knee.