Diabetes type I (DTI) is an autoimmune disease characterized by a progressive destruction of the insulin producing beta cells of the pancreas that requires insulin substitution therapy. Recent epidemiological data show an annual increase of the incidence of DTI of 3.9%. Children with new onset diabetes typically present with polyuria, polydipsia and weight loss. As of today no cure for DTI exists. However new therapeutic immunomodulary approaches are under investigation. In the meantime adherence to insulin therapy is mandatory to achieve near physiological glucose levels. Monogenic forms of diabetes remain rare in children, but their diagnosis is important in order to propose a specific treatment. A critical period for the diabetic patient is the transition from pediatric to adult care.