Th e aim of the research. To study the frequency of genetic polymorphism of genes IL-1β 31T/C and IL-1β 511T/C in patients with gastroesophageal reflux disease (GERD) living in the Trans-Baikal Territory. Material and methods. A total of 139 people residing in the Trans-Baikal Territory for at least three generations were surveyed. Group 1 included 79 patients with GERD (30 male, 49 female), Group 2 (control) included 60 subjects (28 male and 32 female) without clinical and instrumental signs of the disease. The median age was 43 [33; 57] and 44 [37; 54] years, respectively, p = 0.754. Th e groups were matched by the gender, p = 0.16. Th e diagnosis of GERD was established using the GerdQ questionnaire and/or the presence of reflux esophagitis in endoscopic examination and the presence of pathological reflux in impedance pH measurements. Genotyping of interleukin 1 beta (IL-1β) polymorphic genes at positions 31T/C and 511 T/C was performed via the method of polymerase chain reaction. Results. The IL-1β 31C/C genotype was more common in the control group than in GERD patients (OR = 0.302 CI 95 % 0.088-1.034), p = 0.046. The study of the IL-1β 511T/C genotype did not show statistically significant differences in the studied groups. Heartburn one or more times a week was more oft en observed in patients with the IL-1β 511T/T genotype (OR = 11.143 CI 95 % 1.357-91.523), p = 0.0076. Conclusion. Among the population of the Trans-Baikal Territory, the prevalence of the IL-1β 31C/C genotype is higher in persons without clinical and instrumental signs of gastroesophageal refl ux disease. Th e genotypes IL-1β 31T/T and IL-1β 511T/T are more common in GERD patients with the symptomatic course of the disease.