The Polycystic Ovary Syndrome (PCOS) is a heterogeneous disorder, whose principal features include androgen excess, ovulatory dysfunction, and/or polycystic ovaries, and is recognized as one of the most common endocrine/metabolic disorders of women. The pathophysiology of PCOS appears to be multifactorial and polygenic. Current evidence suggests that insulin resistance is an important pathophysiological feature of the polycystic ovary syndrome (PCOS). An important implication of insulin resistance in PCOS is that insulin-sensitizing agents are a useful therapeutic approach in this disorder, as documented by multiple clinical trials. Clomiphene citrate (CC) is currently the first-line therapeutic modality for women with infertility and PCOS. Overall, approximately 80% of all patients receiving clomiphene ovulate and 40% (one-half of those ovulating) conceive. Data suggest that decreased insulin sensitivity, hyperandrogenemia, and obesity, all associated with PCOS, are prominent factors involved in reducing the probability that the ovaries will respond to clomiphene.