The polycystic ovary syndrome (PCOS) is the commonest hormonal disorder to affect women. The cardinal features are menstrual cycle disturbance, hyperandrogenism and polycystic ovaries. Both slim and overweight women with PCOS tend to be more insulin resistant than weight-matched women with normal ovaries. The degree of menstrual irregularity and anovulatory infertility appears to correlate with the degree of hyperinsulinaemia, which in turn correlates with obesity. Lifestyle improvement in the form of diet combined with exercise has been shown to improve reproductive function and the chance of having a healthy pregnancy whether achieved spontaneously or as a result of ovulation induction. The management of anovulatory infertility in PCOS has traditionally involved the use of clomifene citrate and then gonadotropin therapy or laparoscopic ovarian surgery in those who are clomifene resistant. The realisation of an association between hyperinsulinaemia and PCOS has resulted in the use of insulin sensitising agents, such as metformin. We have performed the first adequately powered RCT of metformin versus placebo in anovulatory PCOS and have found significant improvement in menstrual regularity and decline in body weight in both groups, with no benefit from metformin. There are other large RCTs looking at metformin combined with clomifene citrate which have also failed to demonstrate benefit. There is some data, however, to suggest a role for insulin sensitizing and insulin lowering drugs, although algorithms for their place in therapy are still to be agreed. There has been an unfortunate shift away from mono-follicular ovulation induction to the use of in vitro fertilization treatment, based on a false premise of greater cumulative conception rates and appropriate concerns about multiple pregnancy. Superovulation for IVF presents significant risks for women with polycystic ovaries, namely the potentially life-threatening complication of ovarian hyperstimulation syndrome (OHSS). Carefully conducted and monitored ovulation induction can achieve good cumulative conception rates and furthermore, multiple pregnancy rates can be minimized with careful monitoring by ultrasound.