Obesity is an increasing problem around the world and it is blamed to be one of the major causes of some serious diseases such as diabetes mellitus or cardiovascular diseases. Obesity has become epidemic situation in the world as a result of abundance of nutrients and dietary changes and it leads to serious health problems. It occurs due to more body fat accumulation than normal levels, and is associated with many factors. Important risk factors of obesity are dietary habits, female sexualty, age, education, marriage, parity and genetic inheritance. The role of genetic factors in obesity is complex. In humans, obesity occurs either as monogenic syndromes or reflects a multifactorial model of inheritance. Monogenic obesity with an other defini-tion, one gene related obesity is extremely rare and seen together with other genetic disorders. Polygenic obesity is the most common genetic version of obesity, and it presents a multifactorial inheritance pattern. Polygenic obesity occurs as a consequence of the interaction of the genes, environment, behavior with each other.