The prevalence of gastroesophageal reflux disease (GERD) in China is lower than that in the Western countries, but appears to be increasing. The aim of this pilot study was to evaluate the prevalence of GERD in Shanghai, China, and to explore which population characteristics where associated with GERD. A sample of 1200 adult inhabitants of Shanghai, selected using randomized, stratified, multi-stage sampling, completed Mandarin translations of the Reflux Disease Questionnaire and GERD Impact Scale. Potential risk factors for GERD were examined by nested case-control analysis, using Cochran-Armitage trend testing and logistic regression analysis. The response rate was 86.2%; 919 responses were suitable for analysis. The prevalence of GERD, defined as heartburn and/or regurgitation of any frequency during the previous week, was 6.2% in Shanghai. Obesity and urban dwelling were associated with GERD (odds ratio 3.4, 95% confidence interval 1.3-9.3; and odds ratio 3.6, 95% confidence interval 1.2-10.4, respectively). The prevalence of GERD in Shanghai agreed with previous Chinese studies. GERD in Shanghai was associated with obesity and residency in an urban environment.