The cellular composition of all layers of the anterior, central, and posterior parts of the piriform cortex of the rat brain was studied two weeks and one month after specific electrical stimulation (kindling) of the ventral hippocampus. Stereomicroscopic analysis at both two weeks and one month after kindling showed significant decreases in the numbers of pyramidal cells and interneurons in all layers of all parts of the piriform cortex. At two weeks, the numbers of pyramidal cells and interneurons in the central part of the piriform cortex also decreased in rats in which electrodes were inserted into the ventral hippocampus but without stimulation. These results, along with published data, led to a series of suggestions regarding the involvement of the piriform cortex in epileptogenesis