OBJECTIVE: Type 1 diabetes mellitus (T1DM) is associated with other autoimmune diseases such as celiac disease (CD) and Hashimoto thyroiditis. The aim of this study was to evaluate the screening frequency for CD and thyroid antibodies in a multicentre survey. METHODS: The Diabetes Patienten Verlaufsdokumentationssystem (DPV) initiative is based on standardized, prospective, multicentre documentation in children and adolescents with diabetes. Data from 31,104 patients <18 yr of age (52% males, mean age 13.1 yr) with T1DM from 177 paediatric centres in Germany and Austria from 1995 until 2007 were analysed. RESULTS: Of 31,104 patients, 16,994 patients (55%) were screened at least once for CD. In 1995, 44% of the patients were screened for CD compared with 68.6% in 2006. Annual screening for CD has also increased (11.9% in 1995 compared with 43.6% in 2006). Eleven per cent of the patients had positive antibodies for CD. Patients with positive antibodies were significantly younger at diabetes onset and had a significantly longer duration of diabetes (p < 0.001). Compared with screening for CD, screening for thyroid antibodies was performed more frequently (at least once in 62% of the patients). Fifteen per cent of the patients had positive thyroid antibodies. Screening for thyroid antibodies also increased from 62.6 to 72.9%, and annual screening frequency increased from 15.9 to 48.9%. CONCLUSION: Screening for associated autoimmune diseases in children with T1DM has increased during the past decade. Eleven per cent of the patients had positive CD-specific antibodies, and 15% had positive thyroid antibodies. Screening for thyroid antibodies is performed more frequently than screening for CD.