Statement of problem: gastro-esophageal reflux disease (GERD) occurres when there is an insufficiency of the lower esophageal sphincter. The effect of chronic exposure of the oral cavity to gastric acid can be many and varied.Purpose: The purpose of this study was to evaluate the oral and dental manifestations in patients with GERD, and compare them with healthy persons.Material and Methods: In this descriptive and cross-sectional study, 80 patients with GERD, identified by gastroenterologisit, and 80 healthy persons were included. Persons in both groups were asked to answere questionnaires including name, age, consumption of drug, diseases, allergy, bruxism, smoking and dysgeusia. They were also examined for missing teeth, dental erosion and atrophic glossitis. Data were analysed with the spss- 11.5 statistical software by using Mann- Whitney and Chi- square tests.Results: There was a statistically significant difference among two groups for the prevalence and severity of type S2 of dental erosion. (in order Pv=0.045, Pv(S2)= 0.012). No relationship was found between GERD and oral changes including missing teeth, dental sensitivity, dysgeusia, atrophic glossitis and severity of dental erosion (S1, S3) (Pv> 0.05)Conclusion: Moderate dental erosion is a common finding in patients with GERD and should be considered as oral manifestation of this disease.Key words: Gastro-esophageal reflux disease, Dental erosion, Oral manifestations