This study was undertaken to determine if prosthetic suspension capabilities of below-knee amputees could be improved by using biofeedback in a controlled exercise program. Improvements in muscle bulk of four amputees were assessed. Changes in transverse cross-sectional areas and suspension ability of the residual limb were measured. The effect of muscle training on gait and on muscle-use patterns during gait was observed. Marked increases in muscle bulk below the knee and improvement in suspension capabilities were seen in two of the subjects, and somewhat lesser improvements were seen in the remaining two subjects. From these changes, one could modify prosthetic designs to take advantage of the residual limb muscles for suspension. For this reason, training the below-knee amputee to exercise the residual limb musculature should become part of routine physical therapy management. In this study, biofeedback was proven to be a useful tool for the reeducation of the residual limb musculature.