Purpose: Interleukin 1$eta$ (IL-1$eta$) polymorphisms are associated with hypochlorhydria, atrophic gastritis, and increased risk of gastric cancer in Caucasians. We tried to determine whether the IL-1.. and IL-1 receptor antagonist (IL-1 RN) genetic polymorphisms contribute to the development of gastric cancer and the specific type of gastritis in Korean. Materials and Methods: The study population was comprised of 128 gastric cancer patients with histologically proven carcinoma and 63 normal healthy individuals. Sixty-eight carcinomas were of intestinal-type and sixty tumors were of diffuse-type. No patient had a familial gastric cancer history. The 511 bp and 31 bp polymorphisms in the IL-1.. were genotyped by polymerase chain reaction (PCR)-restriction fragment length polymorphism. The polymorphism of the IL-1 RN was analyzed with variable number tandem repeat after PCR. Results: The genotype of 511C/-31T of IL-1$eta$ and allele 1 of IL-1 RN was dominant in the present subjects. The allelic frequencies of the C allele IL-1$eta$, which is a high risk genotype for gastric cancer, were 0.551 and 0.429 in gastric cancer and normal controls, respectively. Statistically, significant difference in allelic frequencies of three polymorphic sites between gastric cancer patients and normal controls, and between intestinal-type and diffuse-type was not observed. Conclusions: These results suggest that the polymorphisms of IL-1$eta$ and IL-1 RN may not contribute to the development of Korean gastric caner and that other endogenous or exogenous factors will be important for gastric carcinogenesis.