Introduction: Septic arthritis is considered the most rapidly destructive joint disease. Arthrodesis of the knee is a salvage procedure that may be indicated for a patient with an infected non-reconstructable knee joint. This study aimed at evaluation of the results of knee arthrodesis using the Ilizarov external fixator to treat septic knee arthritis. Patients and methods: This retrospective study included 11 patients with septic knee arthritis treated with a similar protocol of debridement and arthrodesis by Ilizarov fixator performed from February 2005 to December 2013. The mean age was 46.27 years. Seven patients were males. The cause of septic arthritis was postoperative in six patients, three infected open knee injuries, and two neglected traumatic dislocations. All patients had already undergone previous surgeries with a mean of 3.64 procedures. Patients were evaluated clinically and radiographically. Functional assessment was done by WOMAC index. Results: The mean external fixation period was 5.27 months. The mean follow up period was 30.55 months. One patient sustained femoral fracture after a fall during fixation and managed by proximal frame extension. Six patients had pin track infection and one half pin was broken in a case. Arthrodesis was achieved and infection was controlled in all cases without further procedures. At the last follow-up the mean score of WOMAC index was 27.45. Conclusions: Using Ilizarov fixator for arthrodesis of septic knees was effective in having a stable, mostly pain-free knee, and provided control of infection and improvement in the function and quality of life in such patients.