The goal of treatment in infected nonunion include the elimination of infection, deformity and defects as same time as obtaining union. It is very difficult to obtain union and to correct deformity, infection and shortening in infected nonunion. The purpose of this study is to review the results of treatment of infected nonunion by the Ilizarov technique. Nineteen patients with infected nonunion were treated using Ilizarov external fixator from july 1991 to September 1993. Seven patients are undergoing treatment until now, so those were excluded from this data. Twelve patients were achieved bony union. Eleven cases were united and one case was failed with Ilizarov external fixator. We analyzed twelve cases. There were eleven males and one female, eight tibias and four femurs. Bony union was achieved by direct compression in six cases. Six cases were treated by bifocal osteosynthesis, but five cases were achieved bony union and one case was failed. So, we achieved bony union with intramedullary nailing and bone graft. The results were summarized as follows; 1. Eleven cases of infected nonunion were united with Ilizarov external fixator. The mean time to union of infected nonunion site was 10. 8 months. 2. The average bone lengthening of six cases was 64mm, ranging from 15mm to 110mm. The healing index averaged l. 64 month/Cm. 3, The bone results were excellent in six cases, good in five cases, poor in one case. The functional results were excellent in four cases, good in seven cases, fair in one case. 4. In all cases, we experienced difficulties. So we concluded that Ilizarov technique for infected nonunion is a valid procedure for control of infection, union, bone defect and deformity.