Polycystic ovarian syndrome (PCOS) is the commonest endocrine disorder in women of a reproductive age, occurring in approximately one in seven women. Of these women approximately two-thirds will not ovulate on a regular basis and consequently may therefore seek treatment for ovulation induction. After exclusion of other significant causes of sub-fertility the pragmatic approach to ovulation induction is to commence with clomiphene citrate. The goal of ovulation induction is the development of a single ovulatory follicle and the avoidance of a multiple gestation. Second line therapies consist of gonadotrophin therapy and laparoscopic ovarian drilling, the place of metformin therapy is believed to lie in the management of woman with impaired glucose tolerance. It is imperative that all ovulation induction is performed with access to rapid serum estradiol monitoring and ultrasound facilities. The benefit of the use of aromatase inhibitors has not yet been proven in large studies. Women with PCOS undergoing in vitro fertilization (IVF) are at a substantial risk of ovarian hyperstimulation syndrome and this approach should be avoided if at all possible. If it is required these women may be suitable candidates for in vitro maturation of oocytes (IVM) so avoiding ovarian hyperstimulation. Women with PCOS are potentially at an increased risk of miscarriage and in pregnancy of they are at an increased risk of developing gestational diabetes, pregnancy-induced hypertension and pre-eclampsia. Furthermore the neonate has a significantly higher risk of admission to a neonatal intensive care unit and a higher perinatal mortality.