Polycystic ovary syndrome (PCOS) is one of the most common causes of female infertility, affecting 5-10% of women of reproductive age. The syndrome is characterized by anovulation, hyperandrogenism and polycystic ovaries. Furthermore, PCOS is associated with insulin resistance and obesity, which is present in approximately 50% of women with PCOS. Reproductive function in women with PCOS is strongly dependent on bodyweight and metabolic status. Obesity is associated with an increased risk of infertility and may also have a negative influence on pregnancy outcome. Considering the worldwide epidemic of obesity, clinical problems relating to PCOS may worsen and increase in frequency. Lifestyle interventions resulting in weight loss comprise the most successful strategy to improve symptoms of PCOS. However, many patients fail to lose weight or may quickly regain weight. It is an important challenge to develop effective lifestyle programs and adjuvant pharmacologic treatments in order to improve reproductive and metabolic health among women with PCOS.