Background. Inconsistencies in doctors’ views about causes and treatment of irritable bowel syndrome (IBS) lead to frustration for doctors and in doctor–patient interactions. Diagnosis by GPs does not correspond well to established diagnostic criteria. Objective. To understand GPs’ explanatory models (EMs) and management strategies for IBS. Methods. Qualitative, semi-structured interviews with 30 GPs (15 from the UK and 15 from The Netherlands). Results. Diagnosing IBS in primary care is a complex process, involving symptoms, tests, history and risk calculation. GPs were uncertain about the aetiology of IBS, but often viewed it as a consequence of disordered bowel activity in response to stress, which was viewed as a function of people's responses to their environment. GPs tend to diagnose IBS by exclusion, rather than with formal diagnostic criteria. They endeavoured to present the IBS diagnosis to their patients in a way that they would accept, fearing that many would not be satisfied with a diagnosis that had no apparent physical cause. GPs focused on managing symptoms and reassuring patients. Many GPs felt that patients needed to take the responsibility for managing their IBS and for minimizing its impact on their daily lives. However, the GPs had limited awareness of the extent to which IBS affected their patients’ daily lives. Conclusions. GPs’ diagnostic procedures and EMs for IBS are at odds with patient expectations and current guidelines. Shared discussion of what patients believe to be triggers for symptoms, ways of coping with symptoms and the role of medication may be helpful.