Transplantation of neural progenitor cells (NPCs) has been reported recently to promote regeneration of the injured spinal cord. In the majority of these reports, cell transplantation was performed by local injection with a needle. However, direct injection might be too invasive for clinical use; therefore, the authors investigated a new method of delivering NPCs for the treatment of spinal cord injury. In this study, NPCs were obtained from E15 fetal hippocampus of transgenic rats expressing green fluorescent protein and 100,000 cells were transplanted intravenously into each animal 24h after contusion injury. It was found that the injected NPCs migrated to the lesion site widely and demonstrated nestin at an early phase after transplantation. These NPCs differentiated into neurons, astrocytes and oligodendrocytes, and survived at least for 56 days. These results indicated that intravenously injected neural stem cells migrated into the spinal cord lesion while preserving their potential as NPCs, and that this procedure is a potential method of delivering cells into the lesion for the treatment of spinal cord injury.