The nucleus tractus solitarii (NTS) is the primary site of integration of afferent inputs relayed in the IXth and Xth cranial nerves and, as such, is involved in gastrointestinal, respiratory, and cardiovascular function. 1 This role is clearly of major physiological significance but may also have pathological importance since disruption of NTS function at the gross, cellular, or subcellular level may lead to changes in homeostatic regulatory efficiency. The NTS is also the target for numerous descending inputs from other areas of the CNS and these inputs may function in a regulatory mode, taking advantage of established “homeostatic” or reflex pathways that originate in the NTS, in expressing the autonomic components of response patterns that are an integral part of higher nervous function. This chapter will attempt to review the role of the NTS in these integrative functions, but will restrict consideration to the area of cardiovascular control where there appears to be a more established background literature. Since analyses of NTS function in the in vitro slice preparation indicate a rather homogeneous organization of the NTS in terms of basic neuronal properties and pharmacological sensitivity, at least with regard to areas if not function, then some general guiding principles for the overall role of the NTS may emerge from this restricted perspective.