Background/aims: Recurrent aphthous stomatitis is a common disease of the oral mucosa that is characterized by recurrent, painful ulcers of unknown etiology. The association between celiac disease and recurrent aphthous stomatitis has been evaluated in several studies, but variable results have been reported. The purpose of this study was to determine the prevalence of celiac disease in patients with recurrent aphthous stomatitis. Methods: The study group consisted of 82 patients, all of whom had a history of recurrent aphthous stomatitis. The control group included 82 patients who did not have aphthous stomatitis. Patients were screened for IgA anti-endomysial antibodies, IgG anti-endomysial antibodies, IgA anti-gliadin antibodies, and IgG anti-gliadin antibodies. Patients with positive serology underwent endoscopic biopsies of the duodenal mucosa. Patients in both groups were also questioned regarding gastrointestinal symptoms. Results: One patient (1.2%) out of 82 in the study group was diagnosed with celiac disease by biopsy. Gastroesophageal reflux disease symptoms, heartburn and regurgitation were determined to be of higher incidence in the study group (p<0.001 and p<0.001, respectively). None of the 82 patients in the control group were diagnosed as having celiac disease. Conclusion: It is concluded that there is no apparent etiological link between recurrent aphthous stomatitis and celiac disease and that screening recurrent aphthous stomatitis patients for celiac disease has little clinical value. Additionally, regurgitation of gastric acid to the oral cavity may precipitate the formation of aphthous stomatitis.