The peroxidase-antiperoxidase (PAP) immunohistochemical technique was used to identify neurons in the basolateral amygdaloid nucleus (BL) that contain vasoactive intestinal polypeptide (VIP), somatostatin (SOM) or cholecystokinin (CCK). Examination of immunostained neurons demonstrated that most, if not all, of these peptide-containing cells correspond to spine-sparse class II neurons recognized in Golgi studies. Each type of peptide-containing perikaryon in BL exhibits a distinct size distribution which, in part, accounts for the broad size range of class II neurons noted in Golgi studies.