Our purpose was to evaluate the durability of the diagnosis of irritable bowel syndrome (IBS) based on clinical criteria. The study population consisted of a cohort of previously published study patients evaluated for IBS between 1989 and 1992, who met the International Congress of Gastroenterology criteria for IBS. Patients were reinterviewed for cardinal features of IBS, Rome I, Rome II, and Manning criteria 10-13 years after the initial diagnosis. During the observational follow-up period, there were 75 patients, 14 males and 61 females, with a mean age of 47.5 +/- 11.3 years (SD; range, 20 to 75 years). Mean time of reinterview after initial diagnosis was 11.8 +/- 0.9 years (range, 10 to 13 years). None of the 75 patients had an abdominal condition which could have been mistaken for IBS. Other abdominal conditions diagnosed during this period included diverticulitis (five), uterine fibromyoma (three), and gallbladder disease (three). Sixty-nine patients (92%) did not consider their symptoms as resolved. Thirty-five (46.7%) had repeat structural evaluation of the colon for similar symptoms without any new diagnoses made. Twenty-six (34.7%) and 32 (42.7%) presently meet the Rome II and Rome I criteria for IBS, respectively. Clinicians are advised to use clinical criteria for a specific and durable diagnosis of IBS.