Arthritis has often been alluded to as an extra-intestinal clinical manifestation of coeliac disease, but definitive data regarding its prevalence are still lacking. We therefore evaluated the overall prevalence of articular involvement in 200 consecutive adult coeliac patients attending routine gastroenterology follow-up and in 40 controls, and determined whether the prevalence and pattern of articular involvement varied according to the dietary status. An arthritis was present in 26% of patients and in 7.5% of controls, prevalences ranging from 41% in patients on a regular diet to 21.6% in patients on a gluten-free diet (P < 0.005). Arthritis was peripheral in 19 patients, axial in 15 and an overlap of both in 18 subjects. These data suggest that arthritis is much more common than previous reports have indicated, particularly in patients receiving an appropriate dietary regimen, and support the need for combined gastrointestinal and rheumatological follow-up in coeliac patients.