Hippocampal neuron densities in three areas (H1 zone, end folium, and dentate gyrus) were counted in each of 32 temporal lobectomy excision specimens using the technique of Mouritzen Dam. The association between severe neuronal loss in all three areas and early childhood convulsions that were prolonged and/or lateralized was highly significant. Lesser degrees of neuron loss in H1 and/or end folium were common and were not associated with early childhood convulsions, but were most often found in older patients with a particularly long history of epilepsy.