Restoration of function after spinal cord injury in humans remains an elusive goal despite the extensive progress that has been made in rodent models. Now, investigators have successfully grafted neural progenitor cells derived from human spinal cord into a primate model of spinal cord injury. The grafted cells survived in the rhesus monkeys and expressed neuronal and glial markers. Strikingly, the cells extended thousands of long axons that bridged a cervical spinal cord lesion and formed synapses with host motor neurons. Furthermore, axons from monkey neurons also regenerated into the graft. After several months of growth, the grafts elicited a partial restoration of limb function in the animals. The findings show that stem cell engraftment might be a viable strategy for spinal cord regeneration in humans.