Recent studies have indicated that bone marrow stromal cells (BMSCs) have the potential to improve neurological function when transplanted into animal models of spinal cord injury (SCI). However, it is still unclear how the transplanted BMSCs promote functional recovery after SCI. In this study. therefore, we evaluated how transplanted BMSCs restore the function of the dorsal corticospinal tract (dCST) in the injured spinal cord. Rats were subjected to incomplete SCI, using a pneumatic impact device. Then BMSC suspension or vehicle was transplanted into the rostral site of the SCI at 7 days after the injury. Fluoro-ruby (FR; Molecular Probes), a fluorescent axonal tracer, was injected into the dorsal funiculus of the rostral site of the SCI 63 days after the injury. BMSC transplantation significantly enhanced functional recovery of the hind limbs. The number of FR-labeled fibers in the dCST at the caudal site of the SCI was significantly higher in the BMSC-transplanted animals than in the vehicle-transplanted animals. Some of the engrafted BMSCs were positive for FR, neuronal nuclear antigen (NeuN). and microtubule-associated protein 2 (MAP2) in the gray matter. The findings suggest that the transplanted BMSCs acquire neural cell phenotypes around the injury site and contribute to rebuilding neural circuits, including those in the CST. promoting functional recovery of the hind limbs.