Two experiments were conducted to determine the effect of neurotensin on gastric secretion and gastrointestinal motility in conscious chickens. Chickens were surgically fitted with a cannula to collect secretions from the proventriculus and strain gauge transducers sutured to the gizzard, duodenum, and ileum in order to detect contractions. Peripheral intravenous infusion of physiological levels of neurotensin inhibited pepsin output from the proventriculus, but had no effect on the volume or pH of gastric secretions. Neurotensin also inhibited both the frequency and strength of gastrointestinal contractions when compared to motility patterns following infusion of isotonic 0.9% (wt/vol) saline. The frequency of occurrence of small intestinal refluxes was not affected by neurotensin. These results coupled with our earlier work, which demonstrated that neurotensin is released by the presence of oleic acid in the duodenum, indicate that neurotensin may function as an enterogastrone released by lipids in the gastrointestinal tract of the chicken. This overall inhibitory effect of neurotensin on the avian gut indicates that it is involved in the postprandial regulation of digestion, especially lipid digestion.