Autoradiography was used to localize estrogen- accumulating cells in the amygdala (AMY) of seven adult male rats (85 days old). Two hours after injection with H-E2, the animals were sacrificed and, after processing for autoradiography, the labelled sites in the AMY were studied. The nuclei of the AMY which showed the highest density of estrogen binding (receptors) were nucleus medialis (NM), nucleus corticalis (NCO), nucleus centralis (NCE) and massa intercalata (Ml). These nuclei belong to the phylogenetically older corticomedial part of the AMY. Light to moderate labeling was present in the phylogenetically younger nucleus basomedialis (NBM) and nucleus basolateralis (NBL). Scant labeling was present in nucleus lateralis anterior (NLA) and nucleus lateralis posterior (NLP) both from the phylogenetically younger basolateral pan of the adult male rat AMY. This distribution of estrogen receptors could be related to the biologically more significant influence of estrogen on the regions of response divergence than on regions of sensory convergence in the AMY.