The prevalence of GAD antibodies and its correlation with some autoimmune markers: ICA (islet cells antibodies), antinuclear antibodies, thyroid antithymune and antimicrosomes antibodies, were studied in 84 Tunisian type 1 diabetic children. The prevalence of GAD antibodies was 51.2% and decreased as a function of increasing duration of the disease. Their frequency was 84.6% in children with newly diagnosed diabetes (within 6 months of diagnosis) and only 29.41% in those with a longer duration of the diabetes (more than 5 years). ICA were present less frequently (21.4% of the children). 10.7% of the studied samples were positive with the two antibodies (GAD ab ICA), and 40% were positive only with GAD antibodies. We conclude that the GAD antibodies seems to be more associated to the development of type 1 diabetes than ICA. They are detected more frequently in patients with long standing disease, that's make their determination very interesting as diagnostic and predictive marker.