s / Pancreatology 12 (2012) 502–597 516 investigation of thyroid gland: TSH, FT3, FT4, thyroid echography antithyroid antibodies: thyroid antiperoxidase (antiTPO AB) and antithyroglobulin (antiTg AB) antibodies Results: The antiTPO AB were present in high titers in 85.18% cases (n 1⁄4 46) and in normal titers in 14.81% cases (n 1⁄4 8). The mean values of these antibodies were 416.11 319.11 mIU/ml. We noticed significant differences between patients with positive and negative antiTPO antibodies related with the onset age of diabetes (were younger) (4.86 3.94 vs. 8.62 0.51), the duration of diabetes (much longer) (9.23 4.05 vs. 8.12 0.64 years), the values of HbA1c (more elevated) (8.91 2.03 vs.7.55 1.96%) and the TSH values (much lower) (12.00 23.7 vs. 14.77 17.03 mIU/ml) than those with negative antiTPO AB. (p<0.001). The incidence of positive titers antiTg AB was the same as for antiTPO antibodies. In 45 cases both antibodies were increased. We also noticed significant differences related with ATAB between the age groups 10-14 years and 15-17 years (p <0.001), values being higher in the age group 10-14 years (puberty) to age group 15 -17 years (adolescence), but not between another age groups. Conclusions: Because early age of diabetes mellitus was smaller at patients with positive antiTPO antibodies, it is necessary to determine the possibility of association of autoimmune diseases, especially for thyroid diseases (higher risk for those with autoimmune chronic thyroiditis for hypothyroidism) for all patients with type 1 diabetes mellitus Although it is recommended that antithyroid antibodies, particularly those antiTPO positive to be determinate at children and adolescents with type 1 diabetes at the onset of diabetes, or at the latest before puberty. If the antibodies are positive should be tested the thyroid function and due the thyroid ultrasound to minimize the risk of undiagnosed hypothyroidism in young patients with type 1 diabetes.