OBJECTIVE: Faecal incontinence (FI) is a devastating condition which is well recognised in the elderly and those with certain conditions such as inflammatory bowel disease. However, there is surprisingly little information on its prevalence in irritable bowel syndrome (IBS), especially in relation to bowel habit subtype, and this study aimed to answer this question. DESIGN: 500 consecutive new and follow-up secondary care IBS outpatients (399 female, 101 male, age range 15-87, mean age 46) fulfilling Rome III criteria without any significant concomitant disease were studied. They completed a series of questionnaires documenting FI, IBS severity, IBS subtype, non-colonic symptoms, quality of life, anxiety, depression and any other factors that might be associated with FI. RESULTS: 285 patients (57%) reported FI, which was mild in 68 (23.9%), moderate in 99 (34.7%) and severe in 91 (31.9%) and in response to laxatives in 27 (9.5%) with an equal prevalence in males and females. The prevalence of FI in patients classified as having mild, moderate or severe IBS was 62%, 49.5% and 61%, respectively. The prevalence of incontinence was 65.2% in diarrhoea IBS, 63.7% in alternating IBS and, surprisingly, 37.9% in constipation IBS, where it was in response to laxatives in 35.8%. Compared to continent patients, those with FI had a significantly higher prevalence of urinary incontinence, previous abdominal surgery, pregnancy and vaginal as opposed to caesarean delivery. 23.3% had not disclosed their incontinence to anyone and only 50.6% had told their general practitioner. 66% always carried a change of clothes and 30% used incontinence pads on a regular basis. CONCLUSIONS: The prevalence of FI in these relatively young patients approached that observed in elderly care homes. Hopefully, recognition of this problem will lead to improved management and reduce the trivialisation that unfortunately still continues to surround this condition.