- Objectives Revisions of the diagnostic criteria for irritable bowel syndrome have led to varying prevalence estimates. The Rome III criteria require a lower symptom frequency than Rome II (at least 10% of the time for Rome III, compared with at least 25% of the time for Rome II). In an epidemiological survey of a representative sample of Israeli adults using Rome II, we reported the prevalence for irritable bowel syndrome as 2.9%. The official Rome II integrative questionnaire, used for that study, enables a close approximation of Rome III rates, facilitating a retrospective comparison of these criteria. Methods A representative sample of 1000 adults was interviewed with a validated Hebrew version of the official Rome II integrative questionnaire. The data were re-evaluated retrospectively to compare the Rome II results with a close approximation of the new Rome III criteria. Results The prevalence rates for irritable bowel syndrome were 2.9 and 11.4%, respectively, for Rome II and Rome III. The corresponding consultation rates were 57.1 and 41.7%, indicating that the more strict Rome II criteria may select out a group of patients with more severe disease or greater psychosocial problems. Women made up 71.4% of irritable bowel syndrome by Rome II and 62.5% by Rome III. Conclusions In the present retrospective study, the prevalence rate for irritable bowel syndrome in our population is significantly higher by Rome III compared with Rome II. Rome III may more closely reflect the socioeconomic burden of irritable bowel syndrome compared with the overly strict Rome II. Prospective comparative studies should be conducted to confirm these results.