PURPOSE: Hyperhomocysteinemia was observed in epileptic patients receiving anticonvulsants, especially homozygotes for mtehylenetetrahydrofolate reductase (MTHFR) gene 677C->T mutation. Hyperhomocysteinemia induce atherosclerosis, fetal anticonvulsant syndrome, etc. Therefore, we examined any other factors that might affect the level of homocysteine in epileptic patients. METHODS: We investigated the plasma total homocysteine level in 145 patients with epilepsy. And then we analyzed various factors (clinical findings, neuro-image finding, drugs, MTHFR gene, serum folate and vitamin B12 level) affecting the level of homocysteine. RESULTS: Among the various factors, male, present neurological deficits, frequent seizure attacks, MTHFR gene 677 TT genotype, polypharmacy, and conventional drug (phenytoin, carbamazepine, valproic acid, phenobarbital, primidone, benzodiazpines) than new drug (lamotrigine, vigabatrin, topiramate, oxcarbazepine zonisamide) were related with elevated homocysteine levels. CONCLUSION: We recommend monotherapy with new drugs and higher vitamin requirement in the male epileptic patients of MTHFR TT genotype with neurological deficits and frequent seizure attacks.