Identification with pain has been linked to symptom severity in chronic pain conditions. However, the role of identification with illness in patients with Irritable Bowel Syndrome (IBS) is unknown. We investigated whether participants with IBS show identification with illness and if the degree of illness identification is related to IBS symptom severity and additional physical and psychological variables. In this cross-sectional study, 42 participants with IBS and 41 healthy participants completed an Implicit Association Test (IAT) to measure their level of identification with illness and health. Data on illness duration, explicit illness associations, IBS severity, depression, anxiety, stress and additional symptoms were obtained. IBS participants scored significantly lower on identification with health than healthy participants. The level of health identification was negatively correlated with ‘Nonspecific Somatic Symptoms’. Reduced health identification may be a maintaining factor of IBS that could be targeted with psychological treatments to reduce symptoms. Further, it may be possible to use the IAT to monitor the course of recovery.