Polycystic ovary syndrome (PCOS) is the most common endocrine disease in women and has a significant impact on various aspects of their health and the quality of life. The epidemiology of PCOS is well understood, while the prevalence of this syndrome depends on diagnostic criteria used, the characteristics of the population sample, and vary from 6-10 % to 15 % and higher. A number of studies suggest that the endometrium in women with PCOS differs from the normal endometrium morphologically and functionally. PCOS is associated with infertility problems, higher incidence of pregnancy complications and with increased risk of endometrial cancer, especially when obesity is present.