If one can measure the actual angle of the bowing and rotation of a long bone three-dimensionally, it will be a great help in fracture reductions, operative treatments of the congenital snomalies, determination of the fusion angles in arthrodeses, and so on. We developed a computer program that gives us the actual bowing and rotation angle when we input the angles from the two X-ray films with known angle between them. We measured anteversion and neck-shaft angle of the femur, the amount of bowing and rotation in fracture model, and the fusion angles in arthrodeses. The angles calculated from the computer program were same as those from another X-ray that showed the actual angle taken by derotating the subject.