Antibody assays play an important role in the diagnosis of coeliac disease (coeliac sprue, gluten-sensitive enteropathy), a condition characterized by immunological intolerance to gluten from wheat and from proteins of related cereals in genetically predisposed persons. Enhanced concentrations of IgA-antibodies against tissue transglutaminase or endomysium under gluten-containing normal diet represent an important indication for a biopsy from the small intestine. Demonstration of typical changes in the mucose of the small intestine is still required for the definitive diagnosis of coeliac disease. Recently highly specific antibodies against deamidated gliadin peptides were detected in serum. These antibodies further improve the reliability of serologic diagnosis. The new assays for IgG-antibodies against deamidated gliadin peptides have a very high diagnostic accuracy and are comparable to IgA tissue transglutaminase antibodies. Further investigations have to show whether IgG-antibodies against deamidated gliadin peptides are a reliable disease marker also in case of IgA deficiency. Prospective studies are needed to show whether antibody assays could replace biopsy in the diagnosis of coeliac disease in a substantial number of patients.