Purpose: Management of soft-tissue defect after open tibial fractures includes immediate and repeated debridement, skeletal stabilization, and early soft-tissue coverage with muscle flaps. The purpose of this study was to evaluate the outcome of the free rectus abdominis muscle flap (RA flap) for treatment of open fractures of the tibia and to discuss its advantages compared with the latissimus dorsi muscle flap (LD flap) in poly trauma patients. Materials and Methods: We performed a retrospective review of 5 patients who had a severe (Gustilo IIIb or IIIc) open fracture of the tibia treated with RA flap from May 2003 to March 2006. All were men, and the mean age was 46.6 years (range, $28{sim}68$). Three patients had combined injuries such as pelvic bone fractures, multiple rib fractures with hemothorax, and contralateral tibial fracture. All patients received RA flap within 7 days after trauma except two with established chronic osteomyelitis. Results: All flaps survived, and there was no marginal flap necrosis. During the follow-up period, there was no evidence of persistent or recurrent osteomyelitis. The size of RA flap ranged from $8{sim}20;cm$ in length and $6{sim}10;cm$ in width. The average time required for RA flap elevation was 32 minutes, which is shorter than LD flap. Flap elevation could be done in supine position which is essential in poly trauma patients. Conclusion: Although a wide variety of options are available, RA flap is regarded as an optimal method for coverage of soft-tissue defect of the open tibial fracture in poly trauma patients. LD flap is reserved for large sized soft-tissue defect which cannot be covered by RA flap.