The upper cervical corticospinal tract was transected on one side in adult rats. A suspension of ensheathing cells cultured from adult rat olfactory bulb was injected into the lesion site, This induced unbranched, elongative growth of the cut corticospinal axons, The axons grew through the transplant and continued to regenerate into the denervated caudal host tract, Rats with complete transections and no transplanted cells did not use the forepaw on the lesioned side for directed reaching, Rats in which the transplanted cells had formed a continuous bridge across the lesion exhibited directed forepaw reaching on the lesioned side.*