The aim: To research the association of H. pylori infection in patients with irritable bowel syndrome. Materials and method: In this case control study, 43 patients with IBS (13 males and 30 females) diagnosed according to Rome IV criteria and other 43 controls where included, the patients and control are matched to the gender and age which ranged from 18 to55 years, the study groups were referred to perform a stool antigen test for H. pylori. Results: Presence of H. pylori was compared between patients with IBS and controls using chi-square test. There was signi"cant correlation between the presence of H. pylori and IBS, chi-square = 4.09, P-value = 0.043. The odd ratio for patients with H. pylori to have IBS was 2.53 (95% confidence interval: 1.02- 6.29). There is no signi"cant relationship between type of IBS and presence of H. pylori, chi-square = 2.87, P-value = 0.238. There is no signi"cant relationship between the presence of H. pylori and age, BMI, gender, occupation, or marital state. Conclusions: Results of our study had shown an association of H. pylori infection in patients with IBS, which may propose a link of this infection in IBS pathophysiology.