A 5-year and 10-month old boy was diagnosed with classical type 1 diabetes mellitus (T1DM) without celiac disease. He started on a gluten-free diet after 2–3 week without need of insulin treatment. At the initiation of gluten-free diet, HbA1c was 7.8% and was stabilised at 5.8%–6.0% without insulin therapy. Fasting blood glucose was maintained at 4.0–5.0 mmol/l. At 16 months after diagnosis the fasting blood glucose was 4.1 mmol/l and after 20 months he is still without daily insulin therapy. There was no alteration in glutamic acid decarboxylase positivity. The gluten-free diet was safe and without side effects. The authors propose that the gluten-free diet has prolonged remission in this patient with T1DM and that further trials are indicated.