Obesity has become one of the major problems in today's world. Schools should offer more physical activities and education about healthy lifestyle, at the same time pointing out all harmful effects of inadequate dieting on human body, all with the aim of making adolescents more familiar with the symptoms, treatment, and prevention of diabetes. The aim of this research was to prove the importance of a nurse in educating adolescents about the prevention of diabetes and to determine to what extent young population takes care of their health. The subject of the research was the knowledge of adolescents about diabetes, and how a nurse, with their knowledge and experience, can contribute to that education. A "survey questionnaire" was used as an instrument of this research, according to which one hundred and twenty-seven subjects were tested anonymously. There were thirty-eight male and eighty-nine female subjects involved in the questionnaire. Considering the age, they were divided into three age groups (16, 17 and 18 years of age). The results clearly demonstrate the importance of a nurse in educating adolescents about prevention of diabetes. The knowledge of respondents before education turned out to be lower than it had been expected. The majority of subjects did not know the cause of diabetes, how to treat it, and what the complications of diabetes are. Due to the adolescents' inadequate knowledge on diabetes, nurses and all other health professionals, have a great task - to educate people about healthy dieting and physical activity, with the aim of preventing and controlling diabetes, in order to minimize the number of patients.