Our research team have developed equations that can be used throughout infancy to predict risk for childhood obesity using data from the Born in Bradford (BiB) birth cohort study. Birth weight, weight gain during the first year of life, and maternal body mass index (BMI) were all important factors in predicting risk for childhood obesity. As a next step in this research, we would like to test the validity of our equations in a different sample of UK children. ALSPAC is an ideal candidate for this validation study because of its large sample size and similarity of data to that used to develop the equations in the BiB sample. Bradford has high levels of socio-economic deprivation and ethnic diversity, so validation in the predominately White, middle-high SES ALSPAC sample would allow assessment of the external generalisability of our equations. This work is being conducted as part of a Child Growth Foundation funded project to provide proof of concept that prediction equations for childhood obesity could be developed and incorporated into a mobile phone application for use in primary care practice. We would be happy for the advice and input of interested ALSPAC team members, particulary from those already involved with the BiB study. Any resulting publications from the use of ALSPAC data will acknowledge the study as required.