Abstract: S (somatostatin) is widely distributed in the bodies of different animals from the low invertabrates (such as protozoa) to vertabrates.The distribution of SS in the brain varies in species.In mammalian brain,except cortex,hypothalamus co ntains the highest SS level (Zhou,1989).Evidences for SS innervation in the mam malian and human hypothalamus have been obtained by a number of investigators.Ho wever,the reports are very few in birds.The present paper disclosed the distrib ution of SS-like immunoreactivity in the chicken hypothalamus by using immunocy tochemical (ABC) technique to provide phylogenetical evidence for a better understanding of SS function.