Although gastroesophageal reflux disease (GERD) has been reported to coexist with chronic rhinosinusitis (CRS), it remains controversial whether it increases risk of CRS in adults. This study accesses risk of CRS in adults with newly diagnosed GERD. We identified 15,807 adult patients with newly diagnosed GERD from Taiwan's National Health Insurance Research Database for January 1, 2006 to December 31, 2009. We also randomly selected 47,421 subjects without this disease and matched them with patients by age, sex, index year, and comorbidity to create a control cohort. A Cox proportional hazards model was conducted to estimate the development of CRS, including CRS without nasal polyps and CRS with nasal polyps. Subjects were followed for a median of 2.12 years. In total, CRS developed in 964 (1.52%) of the subjects: 406 patients with GERD (2.57%) and 558 without it (1.18%). After adjustment, those with GERD were found to have a 2.36 times greater risk of CRS (95% confidence interval = 2.08-2.68; P < .001). Risk of this CRS without nasal polyps was higher than the disease with polyps (adjusted hazard ratio: 2.48 vs 1.85). The individuals with GERD in this study were at significantly greater risk of CRS, most often without nasal polyps.