Polycystic ovary syndrome (PCOS) is a diagnosis of exclusion, with other androgen excess and ovulatory dysfunction disorders to be ruled out. There are 3 principal features of the syndrome, including hyperandrogenism, ovulatory dysfunction, and polycystic ovarian morphology. These features have been included in slightly different permutations in the 3 criteria currently available to diagnose PCOS, including that of the National Institutes of Health (NIH) 1990, Rotterdam 2003, and the Androgen Excess Society 2006. Overall, at least 1 in 15 women of reproductive age will be affected by PCOS, making this disorder the most common endocrine abnormality in this age group, with a health burden of over 4 billion dollars in the United States alone.