Background/Aims: Symptom-based criteria have been introduced to aid the diagnosis of irritable bowel syndrome (IBS). Although they have been widely adopted and have proved useful for research purposes by ensuring homogeneity of study populations, there is little information about their utility in routine clinical practice. It was the aim of this study to assess the applicability of the Manning, Rome I and Rome II criteria in the clinical setting and to ascertain how often hospital specialists and general practitioners (GPs) use them. Methods: Hundred secondary-care IBS patients were assessed for their conformity to these criteria. Forty-eight hospital specialists and 68 GPs were asked about their knowledge and utilization of these criteria. Results: Seventy-three percent of IBS patients met Rome II diagnostic criteria with 82 and 94% meeting Rome I and Manning, respectively. Approximately 80% of GPs had no knowledge of any of the specific criteria, and only 4% had ever used them. The majority of specialists had knowledge of the criteria, with 70% having used them. Conclusion: The Rome II criteria are remarkably insensitive and if rigidly applied in the clinical situation would lead to much diagnostic uncertainty. The current lack of interest in them, especially amongst GPs, is unlikely to change unless they can be considerably improved.