Polycystic ovary syndrome (PCOS) is a very common condition affecting up to 18% of reproductive aged women. It is associated with a varied clinical presentation including reproductive (anovulation, menstrual irregularity, infertility and pregnancy complications), metabolic (increased risk factors for and risk of type 2 diabetes mellitus and cardiovascular disease) and psychological (worsened quality of life and increased prevalence of anxiety and depression) dysfunction. Insulin resistance is a key pathophysiological feature of PCOS and worsens the features of PCOS. Obesity and central obesity are also common in PCOS and worsen insulin resistance and the reproductive, metabolic and psychological features of PCOS. Weight management is therefore crucial in PCOS and can be considered as prevention of excess weight gain in lean women, modest weight loss in overweight or obese women and maintenance of a reduced weight long-term. This is advocated as a key initial treatment strategy for the management of PCOS by the recent NHMRC-approved Evidence Based Guidelines for the Assessment and Management of PCOS.