OBJECTIVE To investigate the genetic polymorphisms of interleukin-1B (IL-1B) and interleukin-1 receptor antagonist gene (IL-1RN) in gastric cancer, and to explore the relationships of these genetic polymorphisms to the susceptibility of gastric cancer. METHODS The polymorphisms of IL-1B and IL-1RN genes were analyzed by PCR-restriction fragment length polymorphism (PCR-RFLP) after extracting the genomic DNA from 140 gastric cancer patients and 165 age- and sex-matched healthy controls. RESULTS The polymorphisms of IL-1B promoter region -31, -511 and +3954 locus have no significant difference between gastric cancer patients and healthy subjects. Four kinds of polymorphisms of IL-1RN were found as 2R/2R, 2R/4R, 3R/4R and 4R/4R, and the frequency in gastric cancer patients were 0.7%, 15.7%, 2.9% and 80.7%, respectively, while the frequency in healthy controls were 0, 5.5%, 0 and 94.5%, respectively. Compared to 4R/4R genotype, a 3.37 fold increased risk of gastric cancer were found in 2R/4R genotype, but the difference was not significant (P = 0.557, chi2 = 2.076). IL-1RN 2R allele frequencies in gastric cancer and healthy controls were 8.6% and 2.7%, respectively, which showed the risk to be gastric cancer increased 3.4 times, but the difference was not significant (P = 0.781, chi2 = 0.494). CONCLUSIONS There is no evidence to support that the polymorphism of IL-1B and IL-1RN gene had relationship with gastric cancer. However, the risk of developing gastric cancer might be raised when the IL-1RN 2R allele exist.