Diabetes mellitus (DM) is one of the public health problems of modern society with an increasing trend. Overweight, physical inactivity, especially among young people, and bad habits have a pronounced effect on the development of the disease and, consequently, burden health budgets. According to the Register of people with diabetes in Croatia about 235,000 adults have been diagnosed with diabetes, and the number of patients increases from year to year. Educating patients and their family nurse contributes to the development of measures for the prevention of acute and chronic complications encouraging people to lead an active and fulfilling life with a strong self-control of disease. Education is the process by which the diabetic person with DM acquire the knowledge and skills they need to adapt and control the disease. Education is a key element in the treatment and by continuous education persons acquire skills and knowledge about proper nutrition, therapy, exercise and necessary tools for self-control. Prolonged poorly regulated diabetes leaves heavy consequences for the person and thus the training people with diabetes is a key element in the treatment. The goal of education is to get the patient's will, the strength and motivation to carry out all medical treatments and self-care of disease and thus to maintain and improve the quality of life. The nurse helps the person with DM through a planned and systematic training in controlling the disease.