Abstract The function of vagal gastric and oesophageal mechano-receptors was studied by means of recording the afferent discharges from a single or from several afferent nerve fibers dissected from a gastric and oesophageal branch of the vagal nerve. Three different types of mechano-receptors were found in the gastric wall. Type A: Rapidly-adapting type, situated in the mucous membrane or in the submucosa of the oesophageal border of the cardia, and which do not respond to peristaltic contraction of the stomach wall. Type B: Slowly-adapting type, situated in the muscular layer and responsive to distension and contraction of the stomach. Type C: Slowly-adapting type, connected to the non-myelinated fiber, situated in the muscular layer, and which respond to distension and contraction of the gastric wall. In the oesophagus the same three types were found. However, the number of rapidly-adapting type receptors is far larger than the other type of receptors. It has been concluded that the oesophageal receptors mainly send information about the passing of food and the vagal gastric receptors send information concerning the degree of fullness or emptiness and motility of the stomach.