The effects of the clinically available 5-HT1A agonist, buspirone, were investigated on food intake in food-deprived rats in both nonoperant and operant feeding paradigms. Buspirone (0.5-2.0 mg/kg), administered subcutaneously (s.c.) 15 min prior to presentation of food, produced a dose-related inhibition of food intake in the nonoperant feeding paradigm. The main inhibitory effects of buspirone were apparent during the first 30 min after food presentation. Likewise, in the operant feeding paradigm, buspirone (0.25-1.0 mg/kg, s.c.) produced a dose-related suppression of food intake in the first 30 min after administration. None of the doses of buspirone produced stereotyped or abnormal behavioral changes in the animals. The results of the study, therefore, suggest hat the inhibitory effects of buspirone on food intake in food-deprived rats are unlikely to be due to nonspecific disruptions of behavior. Furthermore, the present findings have important clinical implications with regard to possible ingestive side effects of this drug may have in the treatment of psychiatric disorders.