In total knee joint replacement, the femur and the tibia must be precisely shaped to ensure that they firmly mate with the artificial joint. The normal procedure is to manually cut the bones using a bone saw and mechanical jigs. A 9-axis bone cutting machine tool has been developed by the authors to increase cutting accuracy and reduce the hospital stay required for recuperation. As developed, the cut plane is determined by a 5 degree-of-freedom mechanism and the femur and tibia are cut by moving two translational and one rotational degrees of freedom, a system that provides a cutter path which avoids cutting the ligament. A preoperative planning system based on CAD/CAM principles and an overview of a system for total knee arthroplasty are also discussed. Experimental results showed the effectiveness of the developed robot and the system.