Patients suffering from the irritable bowel syndrome (IBS) tend to have extraintestinal symptoms. The purposes of this study were to compare the nature and severity of these symptoms in IBS patients in relation to patients with inflammatory bowel disease (IBD) and to nonpatients and to clarify the relationship between intestinal and extraintestinal symptoms. A consecutive group of male patients and a control group of age-matched male subjects were studied. Symptoms were graded for severity using a validated, self-administered inventory. There were 53 IBS patients, 55 IBD patients (32 Crohn's disease), and 56 controls. IBS patients scored significantly higher than IBD patients on constipation, dyspepsia, and reflux scales. Musculoskeletal symptoms, neurasthenia, and sleep scores were similar in IBS and IBD patients, and both groups scored significantly higher than the controls. The scores of urinary, thoracic, and oral symptoms were similar in IBD patients and in controls. However, IBS patients scored significantly higher than both groups on all these scales. Reflux symptoms were the most powerful predictors of extraintestinal symptoms, both in IBS and in IBD. Diarrhea was predictive of extraintestinal symptoms only in IBD. In conclusion, IBS patients experienced extraintestinal symptoms to the same extent, or even more than patients with IBD. However, the relationship between intestinal and extraintestinal symptoms differed in the two conditions.