A polymorphism of the apolipoprotein E gene, in particular the epsilon 4 allele (ApoE4), has been associated with impaired neuronal phospholipid metabolism and synapse reorganization and has been implicated in several neurodegenerative disorders. Since selective neuronal cell lose and aberrant axonal reorganization represent hall-marks of Ammon's horn sclerosis (AHS) in patients with chronic temporal lobe epilepsy (TLE), the ApoE polymorphism was studied in 125 patients with TLE. The genotype analysis revealed a frequency of 15.5% for epsilon 4, and 74.8% and 9.8% for epsilon 3 and epsilon 2, respectively. These figures were not significantly different from those reported in the normal European population. In addition, no correlation was found between the ApoE4 allelotype and the age of epilepsy onset, seizure type, febrile seizures, family history of epilepsy, surgical outcome and neuropathological findings in patients with TLE. These data virtually exclude ApoE as a susceptibility gene involved in the pathogenesis of early onset TLE or AHS.