The IgA antiendomysium antibody was found in 99 of 100 consecutive patients with adult untreated coeliac disease, whereas IgA and/or IgG antigliadin antibodies were found in 92 of the same patients. Twenty-nine of them, presenting with minimal, transient or apparently unrelated symptoms (subclinical presentation), were antiendomysium antibody positive, whereas antigliadin antibodies were present in 26. In 33 of them, we also investigated the relationship between circulating antiendomysium antibody and the persistence of jejunal lesions after the institution of a gluten-free diet. Although 24 treated coeliac patients turned out to be antiendomysium antibody negative, in 17 of them jejunal lesions persisted. The present study shows that IgA antiendomysium antibody is a highly sensitive and specific marker for both subclinical and classical coeliac disease, but that it is not a reliable test in the follow up of coeliac patients.