The anatomy of the recently discovered diencephalospinal dopaminergic system is summarized and its possible role in physiological and pathological processes suggested. The cell bodies of origin of this system are localized periventricularly in the dorsal hypothalamus and caudal thalamus, and the terminal innervations are found in the dorsal horn at all spinal levels and around the preganglionic sympathetic neurons in the thoracolumbar spinal cord. Available data favor the participation of the spinal dopaminergic system in pain modulation and autonomic and motor responses. Dysfunction of spinal dopaminergic neurons could be involved in the pathophysiology of certain conditions, such as Parkinson's disease. It appears possible that the beneficial effects of dopamine agonists in this condition as well as some of the side effects of neuroleptics are mediated through their actions on spinal dopaminergic mechanisms.