Intracerebroventricular administration of 0.01–1.0 µg of the peptide FMRFamide (Phe-Met-Arg-Phe-NH2) to mice reduced morphine-induced feeding. Administration of FMRFamide also inhibited feeding induced by a 24-hour period of food deprivation. These results suggest that FMRFamide or FMRFamide-like neuropeptides play an important role in the control of opioid-mediated feeding.