This study was conducted to test the association between the tumor necrosis factor (TNF)-beta gene (B) polymorphism and schizophrenia in the Korean population. 127 patients with schizophrenia according to the DSM-IV criteria and 202 healthy controls were enrolled in this study. Patients and controls were biologically unrelated age and sex-matched native Koreans. Genotyping for the TNFB polymorphism was performed by polymerase chain reaction-restriction fragment length polymorphism. Genotype and allele distributions of the TNFB polymorphism in patients with schizophrenia were significantly different from those of the controls. Subjects with the TNFB*2 allele had an increased risk for schizophrenia (Odds Ratio=1.76, 95% CI=1.27-2.45). The present study suggests that the TNFB polymorphism may confer susceptibility to schizophrenia in the Korean population.