The present study was aimed at examining the interleukin (IL)-10 gene promoter region polymorphic variants in patients with schizophrenia in the Korean population. Two hundred and thirty-three Korean patients diagnosed to have schizophrenia on the basis of Diagnostic and Statistical Manual of Mental Disorders (4th edn; DSM-IV) and 181 normal healthy controls participated in the present study. The DNA was extracted from whole blood using proteinase K and the IL-10 gene promoter region was amplified by polymerase chain reaction. Gene typing was performed by restriction fragment length polymorphism and single-strand conformation polymorphism. Distribution of the alleles and haplotypes in patients with schizophrenia was not significantly different from those of controls. The present study suggests that IL-10 gene promoter polymorphism is not associated with the development of schizophrenia in the Korean population.