In general, severe open fractures of the tibial shaft have been treated initially with external fixation. However, despite many refinements in this technique, it has been associated with numerous complications, including problems at the sites of pins, non-union, delayed union, malunion, and infection. The purpose of this retrospective study is to analyze the results in a consecutive series of patients. There were 8 males and 2 females with an average age of the 44.9 years(range, 26-64 years). The mean follow up period was 23.2 nibtgs(range, 34-120 days). Free flap procedures were performed on all patients. The average time between removal of the fixator and intramedullary nailing was 16.5 days(range, 11-26 days). Indication of conversion to nailing was abscence of any serous discharge, reddness or local heating around pin-sites and normal renge of laboratory data. All 10 fractures had united with additional bone graft in 7 cases. The most frequent complications were delayed union in 7 cases and infection(superficial infection: 6 cases, osteomyelitis: 1 case) after IM nailing. We concluded that pin-tract infection is the major cause of infection after IM nail, but duration of external fixation and time interval(between removal of external fixator and nailing) are not isolated factors.