In order to evaluate vagal cholecystokinin (CCK) binding sites as potential target sites for the satiety actions of CCK, their presence, axonal flow and pharmacological specificity in subdiaphragmatic vagal branches were examined by autoradiography utilizing 125I-Bolton Hunter CCK-33. Specific CCK binding and axonal transport were found in vagal trunks and all abdominal vagal branches. Binding was inhibited by unlabelled CCK-8, but not by desulfated CCK-8. The pharmacological specificity and transport of CCK binding sites to subdiaphragmatic branches indicate a potential role in mediating CCK's satiety effect.