Background: The association between celiac disease (CD) and type 1 diabetes mellitus (DM) is recognized. Most cases of CD in patients with DM are reported to be asymptomatic. Objectives: The objectives of this study were to (1) compare and audit our practice with the published standards for screening for CD in children with DM, (2) characterize the children with DM and biopsy-confirmed CD, in terms of growth and gastrointestinal symptoms, and compare them with children with DM and negative celiac serology, and (3) document the effects of a gluten-free diet (GFD) after 1 year of gastrointestinal symptoms, growth, and insulin requirement. Method: We performed a retrospective case-note review of 22 children with DM, positive celiac serology +/- biopsy-confirmed CD, and 50 children with DM and negative celiac serology. Results: Twenty-two children (3.9% of the total diabetic population) had positive celiac serology on screening, with 17 (3%) having biopsy-confirmed CD. Ninety-four percent of the children had standardized celiac serology testing. At diagnosis of CD, 13 of the 17 biopsy-positive children (76.4%) had >/=1 gastrointestinal symptom. The frequency of gastrointestinal symptoms in negative celiac serology diabetic children was 6% (3 of 50) (P <.0005). Symptoms resolved in all children after introduction of a GFD. A significant improvement in weight SD score (P = .008) and BMI SD score (P = .02) was noted in those compliant with a GFD after 1 year. Conclusions: Children with DM and CD have a higher frequency of gastrointestinal symptoms than their diabetic peers with negative celiac serology and are not truly asymptomatic. Institution of a GFD has a positive effect on nutritional status and symptom resolution in the short-term.