Purpose: This study aim to investigate the occurrence of autoimmune thyroiddisease in children and adolescents at onset of type 1 diabetes mellitus (T1DM) andto assess whether the presence of diabetes-specific autoantibodies can predict theautoimmune thyroid disorder. Methods: Seventy-three children with T1DM were recruited. Glutamic aciddecarboxylase antibodies (GADA), islet cell antibodies (ICA), insulin autoantibodies(IAA), and thyroid antibodies were determined in all patients at the time ofdiagnosis. PResults: The majority of patients (87.7%) had at least one pancreatic antibody(74.0% for GADA, 20.5% for ICA, and 24.7% for IAA). Thyroid autoantibodieswere found in 19 of 73 patients (26.0%) at diagnosis. Thyroid autoimmunity (TA)incidence was not statistically significant by GADA or ICA positivity, but significantlyhigher by IAA positivity (P=0.03), and IAA positivity showed odds ratio, 4.931; 95%confidence interval, 1.323？18.381 for TA. Conclusion: The IAA positivity in children and adolescents with TIDM was stronglyrelated to positivity of thyroid autoantibodies and thus it could serve as an index forearly prediction of the development of the thyroid autoimmune disorder amongchildren and adolescents with TIDM.