Obesity is one of the most common diseases of the modern age and at the same time one of the leading public health problems of the 21st century. The reason for this is the large number of patients, which increases every day, regardless of the fact that this is not an infectious disease. Due to the uncontrolled growth, obesity has taken on a pandemic character, especially because it has a high rate of morbidity and mortality and the increasing costs of treatment. There are a large number of factors that affect the appearance of obesity, and they range from those that can be influenced to those that cannot be influenced. Likewise, obesity is associated with the development of numerous health complications and chronic non-communicable diseases and therefore significantly reduces the quality of life, working capacity and life expectancy, which is another proof that it is a major public health problem. The paper deals with obesity as a public health problem. The paper shows how obesity came to be defined as a disease throughout history. Likewise, apart from the classification of obesity being presented in detail, its causes, aspects on which it affects, as well as the actual situation in the Republic of Croatia and the world, are listed and explained. Finally, the prevention of obesity and the role that nurses and technicians play in the fight against this disease with an uncertain outcome are explained.