The reduced incidence of cancer observed in schizophrenia patients may be related to differences in genetic background. It has been suggested that genetic predisposition towards schizophrenia is associated with reduced vulnerability to lung cancer, and p53 gene is one of the candidate genes. We tested the genetic association between schizophrenia and lung cancer by analyzing polymorphic sites in the p53 gene. Genotype and allele frequencies at two polymorphic sites in the p53 gene (BstUI and MspI restriction sites in exon 4 and intron 6, respectively) were studied in Korean schizophrenia (n=179) and lung cancer patients (n=104). Comparisons of the genotype and allele frequencies of the MspI polymorphism revealed significant differences between schizophrenia and lung cancer patients. The results suggest that the p53 polymorphism specifically found in schizophrenia patients may be associated with reduced vulnerability to lung cancer.