Coeliac disease (CD) is associated with the presence of gliadin antibodies (GA) (IgG and IgA), often used as a screening test for CD. Using a modified micro-enzyme-linked immunosorbent assay for GA, we studied the prevalence of GA in three healthy groups: children (mean age, 12 years), adult blood donors (mean age, 38 years), and healthy women (mean age, 57 years). We also studied the clinical characteristics of the blood donors. On the basis of findings in 27 untreated CD patients, cut-off levels of IgG and IgA antibody titres were chosen to yield a test with relatively low sensitivity (56%) but high specificity (100%). Analysis of IgM antibodies did not improve the sensitivity. Of the 384 12-year-old children, both IgG and IgA GA positivity was found in 15 (3.91%), a rate significantly greater than that in the blood donors (22 of 1537, 1.43%; p < 0.001) or in the middle-aged women (11 of 944, 1.17%; p < 0.0001). Of the 22 GA-positive healthy blood donors, 13 underwent small-bowel biopsy, but only 1 of the specimens manifested histologic changes compatible with CD. The other 12 had normal specimens, including a normal intraepithelial lymphocyte count. The estimated frequency of CD among the blood donors was thus 1 of 1500, a figure consistent with those previously published. We conclude that GA occur frequently in the Swedish population but that their prevalence decreases with increasing age. As a screening test for CD in healthy individuals, the GA titre is of poor predictive value.