Diabetes is a chronic metabolic disease with an unknown cause. In Croatia there is around a thousand children with diabetes. The first symptoms of the disease are: increased thirst, frequent urination, tiredness and lack of energy. Diagnosing the disease is very simple, it includes doing blood tests, whereas the doctor can also an oral glucose tolerance test. Clinical signs of diabetes are: polydipsia, polyphagia, polyuria, weight loss and physical weakness. If the disease is not regulated and controlled, it can cause acute complications, which can also be life threatening if they're not treated and medicated properly. Acute complications include hypoglycemia, which suggests low blood sugar (glucose) and hyperglycemia, also known as high blood sugar (glucose). Chronic complications usually appear many years after setting the diagnosis and are reflected mainly in blood vessel changes, around the heart, eye, kidney... We differentiate between type 1 and type 2 of diabetes. Type 1 is insulin-dependent and is common with children and younger people and necessitates insulin therapy. Type 2 doesn't depend on insulin and is common with people of adult or mature age. Other than insulin therapy, a proper nutrition regime, frequent physical activity and self-control are very important. Treating diabetes also depends greatly upon education of children and their parents about the disease, complications and types of treatment, application of insulin, creating a food regime, the importance of personal hygiene, self-control and keeping a journal.