In the absence of any task, both the brain and spinal cord exhibit spontaneous intrinsic activity organized in a set of functionally-relevant neural networks. However, whether such resting-state networks are interconnected across the brain and spinal cord is unclear. Here, we used a unique scanning protocol to acquire functional images of both brain and cervical spinal cord simultaneously, and examined their spatiotemporal correspondence in humans. We show that the brain and spinal cord activities are strongly correlated during rest periods, and specific spinal cord regions are functionally linked to consistently-reported brain sensorimotor resting-state networks. The functional organization of these networks follow the well-established anatomical principles, including the contralateral correspondence between the spinal hemicords and brain hemispheres, as well as sensory vs motor segregation of neural pathways along the brain-spinal cord axis. Thus, our findings reveal a unified functional organization of sensorimotor networks in the entire central nervous system at rest.