The control of ingestive behavior involves a variety of neurotransmitters, including monoamines, peptides and amino acids. For the past decade many investigators have focused their research on the role that regulatory peptides play in eating behavior. Many peptides, including cholecystokinin, bombesin, calcitonin, corticotropin-releasing factor, neurotensin and somatostatin, have been reported to decrease the amount of food ingested by laboratory animals. In contrast, a relatively small number of peptides increase food intake. The present review describes the effects of these peptides on consummatory behaviors in various species and their sites of action.