Objectives-The main objectives of this study were to assess whether the use of different definitions of irritable bowel syndrome(IBS) could influence measurements of its prevalence and characterize the patient population fulfilling these different diagnostic criteria. Method-A telephone survey was carried out by contacting 8,221 subjects aged ≥ 18 years representative of the French population. A “ screening” questionnaire based on three algorithms of IBS classification (Manning, with or without a notion of a minimal duration of symptoms, Rome I and Rome II) was used by specialised inquirers. Results-Twenty three percent of the subjects interviewed stated that they had suffered from abdominal pain during the previous 12 months.The prevalence of IBS considerably varied, depending on the diagnostic criteria used: 12% based on Manning criteria without reference to the duration of symptoms; 2.5% if the notion of duration of symptoms was added to the Manning criteria,and 2.1% and 1.1% based on the Rome I and Rome II criteria,respectively (the latter includin the same notion of duration). In total, 212 subjects (2.6% ) met at least one of the criteri a including a minimal duration of symptoms, with a predominance for women (sex-ratio close to 2). Conclusion-The prevalence of IBS is strongly dependent on the classification algorithm employed.The requirement of a minimum duration of symptoms eliminates IBS in a large number of subjects complaining of abdominal disorders. Once these methodological variations were taken into account, the prevalence of IBS in France was found to be comparable to that published in international literature. Objectives-The main objectives of this study were to assess whether the use of different definitions of irritable bowel syndrome (IBS) could influence measure of its prevalence and characterize the patient population fulfilling these different diagnostic criteria. Method-A telephone survey was carried out by A “screening” questionnaire based on three algorithms of IBS classification (Manning, with or without a notion of a minimal duration of symptoms, Rome I and Rome II) was used by specialized Results-Twenty three percent of the subjects interviewed stated that they had suffered from abdominal pain during the previous 12 months. The prevalence of IBS distinct varied, depending on the diagnostic criteria used: 12% based on Manning criteria without reference to the duration of symptoms; 2.5% if the notion of duration of symptoms was added to the Manning criteria, and 2.1% and 1.1% based on the Rome I and Rome II criteria, respectively (the latter includin the same notion of duration). In total, 212 subjects (2.6%) met at least one of the criteri a including minimal duration of symptoms, with a predominance for Conclusion -The prevalence of IBS is strongly dependent on the classification algorithm employed. The requirement of a minimum duration of symptom yet IBS in a large number of subjects complaining of abdominal disorders. Once these methodological variations were taken into account, the prevalence of IBS in France was found to be comparable to that published in international literature.