Background: Recurrent aphthous stomatitis (RAS) is a common disease, which several etiologic factors have been considered for it. The infectious agents and immunological factors are the most suspected causes. Recently a few studies with varied results have been done to clarify the role of Helicobacter Pylori (H.pylori) in etiology of RAS. Objective: To find correlations between serum IgG and IgA levels to Helicobacter Pylori and RAS. Patients & methods: A total number of 29 patients with RAS referred to Urmia skin hospital were included in this case-control study. Control group consisted of 57 persons and was chosen from healthy individuals. Blood samples were taken and blood levels of IgG and IgA antibodies of patients and control were measured by ELISA method and collected data were analyzed by chi-square test. Results: IgG antibodies to H.pylori were found in the sera of 75.9% of RAS patients and 66.7% of controls. IgA antibodies were detected in 51.9% of RAS and 70.9% of controls. These differences were not statistically significant. Conclusion: There was no significant difference between IgG and IgA levels to Helicobacter Pylori in patients with RAS compared to control group.