Celiac disease has been shown to be associated with type 1 diabetes mellitus. We conducted this study to determine the frequency of celiac disease in a group of Iranian diabetic children. Ninety-six patients with type 1 diabetes mellitus were tested for anti-tissue transglutaminase antibodies. Six patients (6.25%) were seropositive, and histopathological changes were compatible with celiac disease in intestinal biopsy.