Recent studies have suggested the involvement of Glycogen synthase kinase-3 beta (GSK-3 beta) in pathogenesis and treatment target of schizophrenia and bipolar disorder, which led to consider GSK-3 beta as one of the candidate genes for those disorders. However, the association analysis between GSK-3 beta and either schizophrenia or bipolar disorder is yet to be reported in Korean population. Along with 350 healthy individuals, a sample of 138 schizophrenia and 120 bipolar patients was analyzed for two common SNPs at position -1727 A/T and -50 C/T polymorphism localized in intron 1 of the gene. The results showed that allele, genotype and haplotype distributions for the two SNPs do not differ between the controls and neither schizophrenia nor bipolar disorder patients. We also analyzed the association between the controls and the combined samples of schizophrenia and bipolar disorder, but no association was found. In conclusion, these results suggest that the GSK-3 beta is not associated with the development of schizophrenia and bipolar disorder in Korean population.