Polycystic ovarian syndrome (PCOS) is a common endocrine condition with reproductive and metabolic consequences, including anovulation, infertility and an increased prevalence of diabetes mellitus. Obesity, central obesity and insulin resistance are strongly implicated in its aetiology. Dietary weight loss is recommended as the primary treatment strategy; however, effective means of achieving and maintaining weight loss and reproductive and metabolic improvements are unknown. Lifestyle modification programmes with an emphasis on behavioural management and dietary and exercise interventions have been successful in the general population in reducing the risk of diabetes and the metabolic syndrome, and have had some initial success in improving fertility outcomes in PCOS. However, the literature on effective diet and exercise programmes for PCOS has been sparse, and structured advice for implementing components of lifestyle modification programmes should be assessed in this population.