World Health Organization defines obesity as a disease in which excess fat tissue accumulates to such an extent that it endangers health. To see the severity of obesity as a public health problem there are epidemiological data that show that in the European Union every third eleven year old has excessive body mass or is overweight. For the Republic of Croatia there are data from 2016 that say that 33% of boys and 20% of girls have excessive body mass or obesity. There is a conclusion that obesity is caused by a disproportion between the increase in intake and the reduction in energy consumption. Obesity factors of obesity are divided into genetic factors that affect the development of obesity 40-70% and the environmental factors which include the culturo-socio-economic factors. According to the causal classification, obesity is divided into the primary, which accounts for 97% of all obesity in children and is characterized by the increase in fat mass and secondary classification where excessive thickness is a secondary symptom caused by another disease and takes up to 3% of all obesity. In diagnosing obesity in children, the following methods are used: measuring body weight, height, waist circumference or waist circumference and hips, measuring skin folds and calculating body mass index. The consequences or complications of obesity in children are divided into two groups equally important: physical (physical) and psychosocial consequences. The most common physical consequences are diabetes mellitus type 2, elevated cholesterol levels, sleep apnea and others, while the most common psychosocial consequences are low self-confidence, social isolation, bodyweight, mood disorders, and the like. The simplest method from which all starts is a change of lifestyle, that are changes in diet and nutritional habits and increased physical activity. Modern methods include medication therapy and surgical treatment. All of these methods of treatment have the same goal set for individual access to the baby, which is to achieve long-term optimal body weight in children. Epidemiological data suggesting an increased incidence of obesity in children and the consequences of this disease are evidence of the necessity of obesity prevention. Successful prevention is carried out on an individual, in this case a obese child, his /her family, but also the overall population of the healthy and the one where there is an increased risk of obesity. Prevention is divided into primary, secundary and tertiary. The objectives of the research work on »Obesity in Children« is to check the student's knowledge of obesity in children and examine their views on the subject. For the purpose of the research three hypothetical hypotheses have been devised: 1. Third year students have the highest knowledge of obesity in children by comparing them with the students of the first and second year. 2. More than 60% of students believe that today's parents are unaware of the excessive weight of their children. 3. More than 50% of students consider that primary prevention in the Republic of Croatia is being implemented very small, slightly and insufficient. The research was conducted at the Faculty of Health Sciences University of Rijeka. The respondents were regular students of the first, second and third year undergraduate study of nursing. The student questionnaire method is an anonymous questionnaire survey titled „Survey on knowledge and student opinion on obesity in children“. The survey consists of 16 questions and all the information obtained through this survey remains anonymous and are used exclusively for the purpose of this final work.