The prevalence of obesity in New Zealand children has never been so high. Obesity places the child at increased risk of diabetes, high blood pressure and other health conditions and of course increased mortality as an adult. Nutritional status during foetal development and infancy may play an important role in the development of obesity. Being born large as a result of over-nutrition or being born to an obese mother even when the baby's birthweight is within the normal range, predisposes a child to obesity in later life. Using the detailed demographic, clinical, lifestyle and biomarker information from 2000 pregnant women in the SCOPE study, we aim to identify determinants of obesity in the children at the age of 5 years. This unique study provides the opportunity to gain new insights into the origins of obesity that may lead to novel interventions at the earliest stages of life to prevent childhood obesity.