Polycystic ovary syndrome (PCOS) is a common endocrine disorder that affects 4-12% of women of reproductive age, and is specified when two of the three following criteria are present: hyperandrogenism, oligomenorrhoea and polycystic ovary morphology by ultrasonography. PCOS is characterized by infertility, obesity and hyperinsulinaemia. However, the aetiology of PCOS has not yet been fully identified due to complex metabolic mechanisms. Many researchers have demonstrated that polymorphisms of putative genes related to symptoms are associated with PCOS. In the reproductive system, energy metabolism and hormonal regulation are important to differentiate granulosa cells in the ovary. Peroxisome proliferator-activated receptor gamma (PPAR-gamma) is a transcription factor, and is known to be associated with insulin sensitivity. Furthermore, it is highly expressed in granulosa cells. It was recently reported that various polymorphisms of PPAR-gamma are associated with PCOS in different ethnic backgrounds. This study has shown that both Pro12Ala and His447His polymorphisms of PPAR-gamma are associated with PCOS in a Korean population.