We performed this study to determine the role of polymorphisms of the IL-10 and TNF-alpha promoter genes in the carcinogenesis/pathogenesis of gastric cancer (GC) and peptic ulcer diseases (PUD) in Korea. A total of 232 patients with gastric diseases and 120 healthy controls were included. Polymorphisms of IL-10-1082/-592 gene and TNF-A-308 gene were genotyped by PCR-RFLP. There were no differences in genotypes and allele frequencies of IL-10 and TNF-A polymorphism between study group with GC or PUD and control group. In addition, there were no differences in genotypic frequencies according to H. pylori infection status, location of GC, and histologic type of GC. In conclusion, IL-10-1082/-592 and TNF-A-308 genetic polymorphisms may not be the important contributors to GC in Korea.