OBJECTIVE: As many as 70% of patients with fibromyalgia complain of the symptoms of irritable bowel syndrome (IBS), but there is a clinical impression that IBS patients do not suffer from fibromyalgia as frequently. The sicca complex (dry eyes and mouth) is also commonly observed in fibromyalgia, but its prevalence in IBS has not been evaluated. Our objective was to assess the frequency of fibromyalgia and sicca complex in secondary care patients with IBS. METHODS: Forty-six secondary care patients with IBS and 46 healthy controls were assessed by a rheumatologist for the presence of fibromyalgia and objective evidence of sicca complex (Schirmer and Rose- Bengal tests). Psychological status was also assessed (HAD questionnaire). RESULTS: Thirteen (28%) IBS patients suffered from fibromyalgia, compared with five (11%) controls, a difference of 17% (95% confidence intervals [CI], 2-33%). Fifteen (33%) IBS patients versus three (6%) controls had sicca complex, a difference of 27% (95% CI, 11-45%). CONCLUSIONS: These results suggest that the prevalence of fibromyalgia in IBS is approximately half that of IBS in fibromyalgia. Furthermore, sicca complex seems to be another complaint that should be added to the list of extracolonic manifestations of IBS. Study of the overlap between functional disorders presenting to different specialties may give new insights into the pathophysiology of these puzzling conditions.