This study was aimed to test the association between schizophrenia and a functional serotonin polymorphism (5-HTTLPR) in the upstream regulatory region. Genomic DNA analysis with polymerase chain reaction was used for 5-HTTLPR genotyping. One hundred and eleven patients with schizophrenia and 208 healthy individuals participated in this study. There were significant differences in the negative score and general psychopathology score of the positive and negative syndrome scale according to 5-HTTLPR genotypes and alleles, although no significant differences in allele or genotype frequencies between the two groups were found. These results suggest that 5-HTTLPR may contribute to the susceptibility to the symptomatology of schizophrenia but not to the development of the disorder itself, at least in the Korean population.