OBJECTIVE: Our objective was to determine if a serological marker, the immunoglobulin A antiendomysial antibody (IgA-EMA), can be used to screen for celiac disease in North American children with type 1 diabetes. RESEARCH DESIGN AND METHODS: Subjects included 236 diabetes clinic patients and 56 gastrointestinal clinic patients who underwent intestinal biopsy for suspected malabsorption. Total IgA and IgA-EMA assays were performed. Diabetic patients who were positive for IgA-EMA were asked to undergo biopsy. RESULTS: Of 236 diabetic patients tested, none were IgA deficient and 19 were positive for IgA-EMA (8%). Of 17 patients biopsied, 12 had celiac disease and 3 were symptomatic. The estimated prevalence of celiac disease was 5.1%, consistent with data from European diabetic clinics. Of the 56 gastrointestinal clinic patients, the 3 who were IgA-EMA positive had biopsies diagnostic of celiac disease. Three were found to be IgA deficient, one of whom had celiac disease. Of the 50 IgA-sufficient and IgA-EMA-negative patients, 1 had celiac disease and 49 did not. The IgA-EMA test had a sensitivity of 94% and a specificity of 91% for IgA-sufficient biopsied patients. CONCLUSIONS: IgA-EMA is an appropriate tool for demonstrating an increased prevalence of celiac disease in a North American pediatric diabetic population. Positive testing should be confirmed by intestinal biopsy, and false-positive results require serial follow-up. Symptomatic children require biopsy regardless of their IgA-EMA status.