In this research, mucosal localizations of bombesin, glucagon and somatostatin-14 immunoreactive in some regions of digestive tract of Gallus gallus domestica during the prenatal and postnatal periods were examined using ail immunohistochemical technique. For this purpose 80 embryos (beginning from the 6th day of incubation to end of incubation every days), 5 chicks (a-week-old chick) and 10 adult chicken (45 and 60 days old) were used as material. The sections which taken from proventriculus and gizzard stained immunohistochemically. Bombesin immunoreactive cells were firstly observed in Lamina epithelialis (L. epithelialis) of proventriculus on 17(th) day of incubation (d.i.). Glucagon immunoreactive cells were firstly seen at few numbers in glands of proventriculus and L. epithelialis of gizzard at 9 d.i. Somatostatin-14 immunoreactive cells were firstly observed in stratified epithelium of proventriculus and gizzard at 6 d.i. In adult period, bombesin, glucagon and somatostatin-14 immunoreactive cells weren' t found in glandular epithelium of gizzard.