AIMS: Low HDL cholesterol (HDL-C) levels have been described in patients with coexisting type 1 diabetes mellitus (T1DM) and celiac disease (CD). Data on other possible lipid abnormalities that could further increase cardiovascular risk in these patients are scarce and incomplete. Aim of this retrospective multicenter study was to evaluate whole lipid profiles, besides HDL-C, in children with T1DM associated with biopsy-proven CD, and to investigate the influence of age and degree of adherence to gluten-free diet (GFD) on lipid changes. METHODS: A total of 261 children with both T1DM and CD were enrolled. Serum lipid profiles at CD diagnosis were compared with those after 1 year of GFD and with those of 224 matched children with T1DM alone. The adherence to GFD was judged by means of CD-related antibodies. RESULTS: At CD diagnosis, children with T1DM + CD showed higher LDL cholesterol (LDL-C) compared to children with T1DM alone. Gluten withdrawal failed to normalize LDL-C levels, not even in completely adherent individuals. HbA1c values were not influenced by GFD. The youngest children were characterized at diagnosis by lower levels of total cholesterol and on treatment by a greater decrease in triglycerides levels. CONCLUSIONS: An unfavorable lipid profile, characterized not only by low HDL-C levels but also by high LDL-C values, may increase the risk of cardiovascular disease in children with T1DM and untreated CD. Therefore, a strict gluten-free diet is mandatory in these children, especially the youngest.