The distribution of somatostatin-like immunoreactive (SOM-LI) fibers within the area postrema (AP) of rat and cat, using the peroxidase-anti-peroxidase (PAP) technique, is described. In rat, SOM-LI fibers were scattered throughout the AP while moderate accumulations of SOM-LI fibers occurred near the ventrolateral border. In cat, scattered SOM-LI fibers occurred throughout the caudal AP, with slightly higher numbers present along the AP border with the nucleus tractus solitarius. In rostral AP levels only small patches of scattered SOM-LI fibers were present. AP SOM-LI cell bodies were absent in both species. The immunohistochemical localization of SOM in the AP supports the concept that the gastric and cardiovascular effects of SOM are mediated in part through the AP.