A descriptive histochemical study was performed on the septal area of the rat. Forty adult male albino rats were used weighing (25 0-3 5 Og). The aim of the study was to describe the pattern of distribution of a-naphthyl acetate esterases, succinate dehydrogenase and cytochrome oxidase in the septal area; the results were correlated with the main neural connections of this area. Fresh frozen coronal sections were obtained throughout the septal area; they were stained for the above mentioned enzymes. The results were described in a qualitative manner and a schematic map for each enzyme was drawn. The septal area demonstrated high reactivity for a-naphthyl acetate esterases which was not homogenous among different septal divisions. The highest reactivity was in the perikarya of the neurons of the medial septal division; this was linked to the presence of acetylcholinesterases, these neurons are cholinergic and they are the source of efferents to the hippocampus. Large cells exhibited higher reactivity than smaller one. In the lateral septal division, the main role of esterases was the hydrolysis of neurotransmitters, whereas they are mainly involved in the hydrolysis of lipids and myelin metabolism in the posterior division. The lateral division exhibited the highest reactivity for cytochrome oxidase and succinate dehydrogenase. This reactivity was mainly localized in the neuropil. In the medial septal division, however; the reactivity was high in the perikarya. The main function of these enzymes is probably to provide energy for neurotransmission in the lateral septal division and for synthetic machinery in the medial septal division