The treatment of simultaneous ipsilateral femoral and tibial fractures is a challenging therapeutic problem. Unfortunately, despites a number of reports on these fractures, guidelines for treatment have not been well established. Because the knee joint is isolated partially or completely, the term "floating knee"is used. But most of these injuries are ipsilateral and few bilateral cases were reported in the literatures. The authors reviewed a case of bilateral floating knee treated by 4 intramedullary nails without having any prolonged healing time or limited range of motion in both knee joint postoperatively.