Fibromyalgia and irritable bowel syndrome are both common conditions which account for most of the referrals to physical medicine and rehabilitation-rheumatology and gastroenterology clinics, and they frequently coexist. In this study, we utilized a previously validated questionnaire to assess the prevalence of symptoms of bowel dysfunction and irritable bowel syndrome, and to survey the range of bowel pattern in 75 patients with fibromyalgia as compared to 50 normal controls. Symptoms associated with irritable bowel syndrome (p<0.05) were reported in 41.8% of the fibromyalgia patients and 16% of the normal controls. In conclusion, we found that patients with fibromyalgia have a high prevalence of gastrointestinal complaints confirming the results indicating that fibromyalgia and irritable bowel syndrome frequently coexist. This may suggest a common pathogenic mechanism for both conditions.