Diabetes mellitus is a chronic non-infectious disease with frequent acute and chronic complications. In the world, there is a massive epidemic of people suffering from diabetes, as well as those in whom the disease has not yet been diagnosed. In the world, according to data from the World Health Organization, a little more than half a billion people suffer from diabetes. Diabetes is a disease that cannot be cured, but with proper and responsible behavior it can be achieved that the affected person does not develop severe complications of the disease. With any irresponsible behavior, the affected person puts himself at risk of disability and death. Health professionals often meet patients with diabetes and therefore have a very important role in transmitting information and new knowledge about diabetes. One of the duties of a nurse is to be an educator at all levels of health care. Its task is to educate the population at health care's primary, secondary, and tertiary levels. The goal of the research conducted population of Varaždin County was to see how familiar the citizens are with the prevention, occurrence, and treatment of diabetes. The research was conducted through an online questionnaire to which 182 respondents from Varaždin County answered. The majority of respondents aged 18-25 (63%) took part in the research. Analyzing the questions, it is evident that most respondents answered the questions correctly. This research concludes that the examined sample of the Varaždin County population knows how diabetes is prevented, how it occurs, and how it is ultimately treated. Nurses play a key role in diabetes prevention, treatment, monitoring, education, and support for people with diabetes, as well as their families.