1. By the middle of the last century the hippocampal formation started to be one of the most studied structures of the nervous system. The present study was conducted using 45 albino rats of either sex (150-200 gm) and divided into 3 equal groups. First group was control and received water and food ad-libitum, second group was experimental receiving chronic depression for 7 weeks by immobilization method, the third group received Flouxetine drug (1mg/kg body weight orally) for 4 weeks following chronic depression. The animals were sacrificed after the experiment, perfused with 10% formaldehyde, brains were dissected and tissue blocks were processed for paraffin embedding. Observations were made on 5 micron thick H and E stained sections. Estimation of neuronal density of CA4 regions was performed using Motic images plus 2.0 software. Neuronal density was markedly reduced (85.4 cells/cubic mm) in experimental group, as compared to control (110.5 cells/cubic mm). Neuronal density was enhanced to 144.3 cells /cubic mm in Treatment Group. Statistical analysis was done using students t-test and the significance was assessed. It was found that stress induced depression causes significant neuronal loss in CA4 region that can be significantly reversed by the pharmacological intervention.