INTRODUCTION: Irritable bowel syndrome (IBS) and functional dyspepsia (FD) are highly prevalent in the general population as does gastroesophageal reflux disease (GERD). Therefore, it is expected that these conditions may frequently overlap. OBJECTIVE: We aimed at evaluating the presence ofFD and IBS symptoms in patients with erosive (ERD), non-erosive reflux disease (NERD) and Barrett's esophagus (BE). PATIENTS AND METHODS: 71 patients presenting at the reflux disease outpatient clinic were prospectively included in this study. 33 patients had NERD, 25 ERD and 13 BE according to the Montreal classification. All patients with ERD and NERD had typical reflux symptoms, as assessed by a validated GERD questionnaire (RDQ). The diagnosis of functional dyspepsia and IBS symptoms was assessed according to the Rome III criteria. RESULTS: IBS symptoms (bloating, abdominal pain, constipation and diarrhea) were slightly more prevalent in NERD (54.6, 63.6, 21.20, 24.2%, respectively) than in ERD (48.0, 44.0, 12.0, 20.0%, respectively) and in BE (53.9, 23.10, 15,4, 23.1%, respectively), but none of these differences reached statistical significance. NERD patients had more FD symptoms than patients with ERD or BE, but again this difference did not reach statistical significance. CONCLUSION: Our data show that IBS and FD are common in the entire spectrum of GERD. The presence of these disorders might explain why many patients with GERD are deemed as treatment failures if they have no complete symptom relief with proton pump inhibitors.