The purpose of this study was to evaluate the diagnostic value of gliadin antibodies (GA) in coeliac disease. The test was a diffusion in gel enzyme-linked immunosorbent assay (DIG-ELISA), with combined determination of IgA and IgG. The sensitivity, specificity, and positive and negative predictive value of the test were determined, as used on a well-described, consecutive material of 100 adult patients, admitted for small-intestinal biopsy. For comparison, the positive predictive value of the test, when used on a larger Danish patient material of adults and children, was determined. One hundred and eighteen adults and 55 children with increased or borderline GA were included. For adults the positive predictive value was 71-90%, the negative predictive value 97%, sensitivity 77%, and specificity 95%. For children the positive predictive value was 74%. A graded interpretation, improving the usefulness of the test, is proposed. It is concluded that GA are useful in screening for coeliac disease (CD). It is still necessary to perform at least one small-intestinal biopsy to establish the diagnosis. Highly elevated GA levels strongly indicate CD, whereas a result well below limits makes CD unlikely.