Antigliadin antibodies (AGA), both IgA and IgG, were studied in the serum of 84 coeliac children during the various stage (Diagnosis, GFD, Challenge) and in 29 healthy children, with a micro-ELISA technique. The results demonstrated the presence of AGA in the serum of coeliac children and a different behaviour between the two Ig-classes in the various stages of the disease. During acute phase both classes were present at high titre. When gluten was withdrawal from the diet, while the titre of IgA fell rapidly since the first month, the IgG titre decreased slowly and raised the normal limits after six months. If the children didn't observe a corrected GFD, the serum AGA titres remained at high levels. During challenge, while IgG raised since the early days, IgA titres raised later, when the intestinal damage became important. The explanation of this different behaviour could be that AGA-IgA are derived from gut mucosa, on the contrary AGA-IgG are not synthesised in the intestine. We believe that serum AGA seem to be good markers of the immune reaction in the intestine triggered by gluten. Furthermore we conclude that the assay of AGA in the serum of coeliac patients is: 1) high sensible and specific method; 2) the most important screening test for intestinal biopsy; 3) the most important test for diagnosis and follow-up of CD; 4) the test which could substitute 1 or 2 intestinal biopsies of the ESPGAN protocol.