The objective of this study was to develop injury risk functions for the Large Omni-directional Child (LODC) ATD abdomen and thorax. Paediatric specimen biomechanical data were gathered from literature, and thorax deflection and abdomen pressure were collected when the LODC was tested in the same conditions. Using the assumption of biofidelity and the measured relationships between various LODC responses, abdomen pressure and thorax deflection, compression, and velocity were estimated for paediatric specimen tests and used with the paediatric injury outcomes to construct risk functions. The _maximum abdomen pressure associated with 50% risk of AIS3+ injury was found to be 114.5 kPa. LODC sled test data in various restraint conditions associated with low (e.g. 5-point harness) and high (e.g. submarining in lap belt only) probability of abdominal injury aligned well with the injury risk function. For the thorax, V_max*C_max was found to be the strongest predictor of thoracic injury, with a 50% risk of AIS2+ injury of 0.45 m/s. The accuracy of the thorax risk function was evaluated using LODC data from several restraint conditions, real-world cases using LODC response relationships, and literaturereported V_max*C_max injury thresholds for adult specimens.