Background: Coeliac disease is common yet often undiagnosed because symptoms may be trivial, non-specific, or non-gastrointestinal, or because of lack of clinician awareness. Serum IgA-class endomysial antibodies (EmA) have high specificity for coeliac disease and may facilitate case-finding by clinicians other than gastroenterologists. We assessed the appropriateness and diagnostic yield of of requests for EmA by primary care general practitioners in a defined geographic area of Northern Ireland. Methods: We identified patients who had EmA examination requests by their general practitioners during 1994-1996. Individual patient questionnaires were posted to the general practitioners concerned, seeking information on indications for testing, management after the result, and final diagnosis. We compared new patient diagnosis rates in two catchment areas, one served by a large district general hospital with, and the other by smaller hospitals without, a medical gastroenterology facility. Results: A total of 239 patients had coeliac profile testing by 69 of 177 general practitioners in the area. Data were available for 181 patients not previously known to have coeliac disease, of whom 20 (11%) had EmA. All EmA-positive patients were referred to hospital, where 19 underwent small-bowel biopsy, which confirmed coeliac disease in all 19. Only 7 (35%) of the 20 had diarrhoea, and there was no significant difference in EmA prevalence among patients tested with and without diarrhoea. Although the mean number of new patients (per 100,000 population annually) diagnosed by biopsy was 11 at the large hospital compared with 5 elsewhere, the numbers identified by EmA in general practice for the 2 catchment areas were similar (2 and 3, respectively). Conclusion: General practitioners have an important role in the identification of patients with coeliac disease, particularly where there is no local medical gastroenterology facility, and this is facilitated by EmA testing.