Background: Ghrelin is a hormone related to food intake in rodents and humans, mainly produced in stomach. This study aimed to determine the effect of irradiation on ghrelin concentration in the gastric mucosa of rats. Materials and Methods : Twenty-five rats were exposed to 15 Gy of whole-abdominal irradiation. Gastric tissue samples were obtained 1, 3, 7, 30, and 90 days after irradiation. Five non-irradiated rats were used as controls. The number of ghrelin cells that reacted with anti-ghrelin antibody was counted. Moreover, ghrelin mRNA expression was determined. Food intake and body weight changes were measured simultaneously. Results: Compared to the controls, irradiated rats showed a significantly decreased gastric ghrelin cell count, i.e., 29%, 30%, 32%, and 32% at 1, 3, 30, and 90 days, respectively, after irradiation (p < 0.05). Irradiated rats also showed decreased ghrelin mRNA expression the expression decreased by 54.1%, 58.8%, 52.0%, and 52.7% at 1, 3, 30, and 90 days, respectively (p < 0.05). Food intake of irradiated rats decreased continuously compared with the control rats, except at 90 days. Body weight of the irradiated rats was lower than that of the controls at 7 and 30 days. Conclusion: This study demonstrated that abdominal irradiation can reduce gastric ghrelin concentration. Though decrease of food intake and body weight was observed simultaneously, further evaluation needs to find out the relationship between gastric ghrelin level and food intake after exposure to irradiation.