The purpose of the present study was to examine the association between the tumor necrosis factor (TNF)-alpha gene (A) polymorphism and schizophrenia in a Korean sample of schizophrenic patients and control subjects. Genotyping for the TNFA polymorphism was performed by polymerase chain reaction-restriction fragment length polymorphism. Genotype and allele distributions of the TNFA polymorphism between schizophrenic patients and controls were not significantly different. In the light of these results, the TNFA polymorphism seems not to confer susceptibility to the pathogenesis of schizophrenia, at least in the Korean population.