It is nowadays well known that there are reflex loops starting in the spinal cord, relaying in various supraspinal structures and descending back to the cord. These long-loops regulate motor responses and work in cooperation with segmental mono- and polysynaptic reflexes. The role of certain well-documented long-loop reflexes is reviewed. The existence of additional long-loop reflexes is hypothetized and preliminary results supporting this view are presented. In discussing the mode of action of spinal cord stimulation, the various ascending and descending pathways involved in long-loop regulation of motricity are to be taken into account.