The present study was aimed to identify the association of overweight and obesity with gastroesophageal reflux disease (GERD). This age- and sex-matched case-control study was carried out in a sample of subjects referred to the specialized clinic of Tabriz University of Medical Sciences from November 2006 to March 2007. Data were collected using a demographic questionnaire and a checklist to determine reflux symptoms. Weight and height were measured and Body Mass Index (BMI) was calculated. Logistic regression was used to examine the association between overweight, obesity and reflux symptoms. The study population included 106 cases (with reflux symptoms) and 111 controls with a mean age of 35.2 +/- 12.9 years. The mean BMI was 2.4 units greater in cases than controls (p = 0.0001). In unadjusted model, overweight (OR = 3.41, CI: 1.8-6.44) and obesity (OR = 2.84, CI: 1.38-5.82) were significantly associated with GERD. Results of multivariate logistic regression revealed significant association between overweight and GERD after adjusting for confounders (OR = 2.87, CI: 1.49-5.53). Given the increasing prevalence of patients with both overweight/obesity and GERD, Serious dietary intervention studies for weight loss as a therapeutic strategy should be carried out in GERD patients complicated with obesity.