The calcium binding protein calbindin D28k (CaBP) is localized in the granule cells of the dentate gyrus, in pyramidal neurons of the CA1 and CA2 subfields of the Ammon's horn as well as in distinct groups of local circuit neurons in both parts of the human hippocampal formation. Immunostaining was performed on human brain perfused 2 h after death. The localization of CaBP in the human was found to be similar to that in the monkey hippocampus suggesting that there is no species difference in the cellular localization of CaBP among different primates.