Twenty five cases of fractures of the femur & tibia on the same leg (floating knee) in 24 patients were treated in St. Mary's Hospital, Catholic Medical College and Center during the period 1977-1985. We studied all of these patients, divided by four groups according to the methods of treatment, retrospectively with analysis of treatment and end result. Our policy of treatment for these multiple fractures in single extremity was directed toward early weight bearing, active and passive knee exercise by early open reduction and rigid internal fixation for both fractures. The results obtained were as follows: l. Of 25 cases, 20 patients were male and 5 were female. 2. The right lower extremity has constituted 56% of the cases. 3. Average age of patients were 37 years. 4. Most common level of fractures was on middle one third of femur (71.4% ) and proximal one third of tibia (46.2%). Of these 25 cases, three cases of femur and one case of tibia were segmental fractures, and one case of femur and five cases of tibia were open fractures initially. 5. Of 28 cases of femur fracture, 23 were given operative treatment and five conservative method. But out of 26 cases of tibia fracture, each half cases of fracture were treated operatively and conservatively. 6. We analysed the final results of treatment by the time of fracture union roentgenologically and five lower limb functions clinically at the termination of treatment. The average time for fracture union was 20.5 weeks for femur and 21.9 weeks for tibia roentgenologically. The acceptable clinical results could be achieved in 18 cases (72%) of early open reduction and rigid internal fixation for both tibia and femur as early as possible after accident for early knee exercises. 7. The status of fractured tibia was the most important factor to treat these multiple fractures in single extremity because of troublesome to start knee exercise and weight bearing.