BACKGROUND/AIMS: Epidemiological studies suggest that there is a considerable overlap between functional dyspepsia (FD) and irritable bowel syndrome (IBS). The aim of this study was to examine concurrent gastrointestinal symptoms in FD and IBS. METHODS: A total of 186 college students filled out a questionnaire regarding whether they had uninvestigated dyspepsia (UD, FD without endoscopic examination) and IBS based on Rome-II criteria. Gastrointestinal symptoms were measured using the Gastrointestinal Symptom Rating Scale (GSRS) questionnaire. RESULTS: A total of 181 students (98 males, mean age 24.6 years) completed both questionnaires. The prevalence of UD, IBS, and UD+IBS overlap was 12 (6.7%), 40 (22.1%), and 8 (4.4%), respectively. A significant UD+IBS overlap was observed (66.7% IBS in UD, 20.0% UD in IBS). Reflux scores of GSRS in either UD or IBS were significantly greater than in those without. Gastroesophageal reflux disease (GERD), defined as weekly occurring moderate symptoms of heartburn and/or acid regurgitation and evaluated using the GSRS, was found in 16 (8.8%) of the subjects. The prevalence of IBS was significantly higher in GERD patients than in non-GERD patients (50.0% vs 19.4%). CONCLUSIONS: The considerable overlap not only between UD and IBS, but also between GERD and IBS, suggests the involvement of common pathophysiological disturbances in the two conditions.