From July 1989 to February 1993, twelve patients were analysed for infected bone loss which treated with radically debriding all infected dead bone and closed suction-irrigation system with antibiotics and internal lengthening by using the external fixator. The results are summarized as follows. 1, The average time for application of external fixation was 30.7 weeks in tibia, 27 weeks in femur and average time for bone union was 31.5 weeks in femur, 34.2 weeks in tibia. 2. Soft tissue defects were treated with split thickness skin graft in 6 cases, secondary closure in 4 cases, gastrocnemius rotational flap in 2 cases. 3. The length of bone defects after infected bone excision ranged from 2cm to 9.3cm, averaging 4.5cm. The bone defect was treated by internal lengthening after corticotomy with the Ilizarov apparatus in 4 cases, the Orthofix external fixator in 8 cases. 4. Four cases in this series were complicated; one pin tract infection, one angulation deformity, one checkrein deformity, one flexion contracture of knee joint. 5. Infection was managed with radical debriding infected dead bone and closed suction-irrigation system with antibiotics in all cases. 6. We recommend that the infected bone loss can be effectively managed with radically debriding dead bone and closed suction-irrigation system with antibiotics and lengthening with Ilizarov apparatus or Orthofix external fixator.