BACKGROUND: Little is known about the relationship between acute exacerbations of COPD (AECOPD) and gastroesophageal reflux disease (GERD). The aim of this study was to investigate the effects on AECOPD of GERD diagnosed by a questionnaire. METHODS: The subjects were 221 consecutive patients with stable COPD who were evaluated using the Frequency Scale for Symptoms of GERD (FSSG) and a prospective survey of AECOPD for one year. Patients taking drugs for acid suppression were excluded. The association between the frequency of AECOPD and the presence of GERD or FSSG score was examined. RESULTS: Based on the FSSG, the prevalence of GERD was 26.7%. AECOPD and hospitalization due to AECOPD were significantly more frequent in patients with GERD than in those without GERD, with crude relative risks of 3.42 and 3.66, respectively. Multivariate analyses showed that GERD and COPD stage IV were significant predictors of hospitalization due to AECOPD, independent of respiratory therapies or patient characteristics. The severity of GERD symptoms, as measured by the FSSG score, was significantly correlated with the frequencies of AECOPD and hospitalization due to AECOPD. Similar correlations were seen for the FSSG subscores for acid reflux and gastric dysmotility. CONCLUSIONS: This prospective cohort study showed that GERD appears to be a predictive factor for hospitalization due to AECOPD and that severer GERD symptoms may be associated with more frequent AECOPD. Thus, further studies are warranted to evaluate the preventive effect of the therapy for GERD on AECOPD.