To evaluate quantitatively the contribution of each muscle to amputee gait during level walking and stair climbing in transfemoral amputees and healthy individuals, gait analysis and electromyography with transfemoral amputees (n = 8) and healthy adults (n = 10) were performed to evaluate muscle balance during each ambulatory task. Time - distance and kinematic parameters by gait analysis were calculated, and the rms EMG of major muscles and hamstring and tibialis anterior coactivity were measured by electromyography. Most kinematic parameters showed no statistical difference between each task, excluding pelvic tilt, pelvic obliquity and hip abduction. Major muscle activities and coactivities of hamstring and tibialis anterior showed that the stair ascent task needed excessive muscle activity compared with the stair descent task and level walking, and that muscle activity and coactivity of amputees were greater than those of healthy individuals, excluding hamstring coactivity during stair ascent (p < 0.05).