Irritable bowel syndrome (IBS) has been reported in 10 to 22% of adults. Using a semi-structured clinical interview to study the prevalence of irritable bowel syndrome, we compared 41 patients seeking treatment for panic disorder in an outpatient setting to an age- and sex-matched control group of 40 patients who were seeking treatment in a general physician's office for other medical illnesses. The control group did not have any Axis I disorders. IBS was diagnosed according to the criteria of Drossman et al. Nineteen (46.3%) patients with panic disorder met the criteria for IBS, in contrast to one (2.5%) patient in the control group (p < 0.000005). Patients with panic disorder and IBS were more likely to report symptoms of back pain as well as a personal history of bowel disease compared to patients with panic disorder but without IBS. IBS is fairly common in patients seeking treatment for panic disorder. Prospective studies should address the question whether treatment of panic disorder leads to an improvement or resolution of the symptoms of IBS.