The gastric phase of gastric secretion is well documented. The object of this study was to estimate the relationship between the host and the graft stomach in rats. Our findings revealed individual variations in total gastric secretion, while the mean secretory volume in syngeneic transplants remained relatively constant throughout the observation period. No significant changes in the secretion of free acid or pepsin were noted. Histologic studies were made of the myenteric nerve plexus and submucosal muscle. The creation of various models of gastric pouches and transplantation of the stomach have added valuable data to gastric physiology and transplant immunology.