The technology of frying is one of the most - important and popular methods of cooking food, widely used in restaurants, companies engaged in catering and in many other food industries. The main principles of deep frying in oil bath are as follows: fresh oil - delivered and inspected by a licensed provider, the amount of fried items, load the cooking trays for hours and days; multiplicity of adding fresh oil, form, structure and capacity of professional fryers used in the restaurant and food industry, chemical changes that occur in fat; principle effects of heat and moisture transfer during frying; fast and objective methods to control the oil. The main purpose of our book review was to investigate previous researches in this area and to present our knowledge about oxidative degradation processes in fat during frying in the cooking product. The study of these processes is of great importance for our time, because it defines the quality of fried foods and semi-finished products, as they can be a potential risk to human health.