Obesity is a chronic metabolic disease which is characterized by an increased body fat. Obesity increases cardiovascular morbidity and mortality and presents an important socioeconomic burden for the health system. So-called “central-android-abdominal-visceral” obesity plays an important role in the development of cardiovascular diseases. Adipose tissue is nowadays considered to be metabolically active tissue which is involved in many metabolic processes, managing food intake, lipid metabolism regulation, and also inflammatory diseases. Many cytokines, such as those regulating body temperature, are produced by the adipose tissue. In the last few years, many studies of ectopic adipose tissue including epicardial fat were published. This is a complex organ which consists of adipocytes, stromal cells, macrophages, and network of neural cells and blood capillaries. This thesis summarizes updated information regarding physiological and pathophysiological role of epicardial fat, epicardial fat measurement and a possible connection with common diseases, such as ischemic heart disease, cardiac arrhythmias, diabetes mellitus, chronic obstructive pulmonary disease and disease of thyroid gland.