Sera from 162 Saudi Arab children were examined for autoantibodies to thyroid microsomes, thyroglobulin pancreatic islet cells, gastric parietal cells, and adrenocortical cells. The subjects included a control group (n = 76) and 86 children below 14 years with Type 1 diabetes. Antithyroid antibodies were detected in 8.1% of the diabetic group and in none of the control group. Parietal cell antibodies were found in 9.3% of the diabetic group and 4.4% of the control group; 14.6% of diabetic children and 2.2% of control children were positive for islet antibodies. However, 56.3% (9/16) of those who were tested at onset of diabetes had positive islet antibodies. In none of the children could we detect adrenocortical cell antibodies.