The IgA antigliadin antibodies AGA title was detected in 37 patients with IDDM, mean age 32.59 +/- 14.71, where mean duration of disease was 8.76 +/- 9.62 years, and 29 patients with NIDDM, mean age 55.31 +/- 14.71, where disease lasted 11.5 +/- 5.55 years. A group of 51 normal pts. was employed as control. In IDDM group 2 cases on 37 showed high AGA title (case n. 1 and n. 2) but just the case n. 1 where IDDM lasted 16 years, showed an histologic picture of coeliac disease (partial villous atrophy), while in the case n. 2 where IDDM was at the onset, the histologic picture was normal. The increase of AGA title in the IDDM at the onset is rarely associated with coeliac disease, but it seems to be an aspecific response. Viceversa an increased AGA title is in IDDM for greater than 1 years often associated with coeliac disease. In NIDDM no high AGA title was found. The prevalence of coeliac disease in our patients with IDDM was 1:37 and we suggest that diabetics be screened routinely for antigliadin antibody.