Although childhood obesity is extensively researched, a gap remains in longitudinal studies comprehensively examining early predictors using rich, multidimensional data collected from birth through to early childhood. ORIGINS1 offers a uniquely comprehensive longitudinal dataset, tracking approximately 10,000 families in Western Australia from pregnancy through early childhood. This project will be using ORIGINS data to explore risk and protective factors of obesity from birth to early childhood. An initial step is to explore the rates of obesity in early childhood in a smaller sub-set of the ORIGINS cohort at the ages of 1, 3 and 5 years. Children’s Body Mass Index (BMI) z-score were classified using the World Health Organization BMI-for-age cut-offs2. At 1 year of age children (n=1,853) were classified as: thinness (1%), healthy weight (71.7%), and overweight or obese (27.2%). At 3 years of age children (n=1,526) were classified as: thinness (4.3%), healthy weight (78.5%), overweight or obese (17.2%). At 5 years of age children (n=868) were classified as: thinness (3%), healthy weight (78.7%) and overweight or obese (18.3%). Overall, it appears that the majority of children were classified as heathy weight, which remains stable from 1-5 years. The proportion of participants classified as overweight or obese appears to be the highest at 1 year, reduce slightly at 3 years and increase at 5 years. This data provides good insight into the trajectories in early childhood BMI status. However, further exploration is required to ascertain the most appropriate body composition cut-offs to be implemented during early childhood.