The hypothalamus has long been thought to play a critical role in regulating the autonomic nervous system, but the connections that allow this control are not known. We used retrograde transport of horseradish peroxidase from the intermediolateral column in the spinal cord and dorsal vagal complex in the medulla to identify neurons in the paraventricular nucleus and lateral hypothalamus with projections to these sites. We then showed by anterograde axonal transport of tritiated amino acids that these hypothalamic neurons innervate all of the parasympathetic and sympathetic preganglionic nuclei in the medulla and the spinal cord, as well as the nucleus of the solitary tract, the site of termination of visceral sensory afferents. These monosynaptic pathways are likely to play an important role in integrating autonomic response with behavior and endocrine control.This article is part of a Special Issue entitled SI:50th Anniversary Issue.