Fas-associated phosphatase-1 (FAP-1) is a regulatory peptide inhibiting apoptotic signal transduction via the death receptor Fas. Because apoptosis is a common mechanism leading to neuronal death in neurodegenerative disorders, the authors investigated the immunohistochemical distribution of FAP-1 in the hippocampus of elderly control subjects and Alzheimer disease (AD) patients. The current study provides the first evidence that FAP-1 is localized in the human hippocampus in pyramidal neurons of the hippocampal subfields CA1-4 and in granular cells. Cellular and extracellular FAP-1 intensity was increased in some control subjects and AD patients, but was not related to the stage of the illness. Rather, these data may indicate a general role for FAP-1 in neuronal death both in adult CNS and during the course of neurodegenerative disorders.