Models for oxygen transport in preterm infants can aid the development and evaluation of automated oxygen controllers by providing insight into the FiO2-SpO2 response and enabling virtual trials. A computer simulation model of oxygen transport in preterm infants is developed and FiO2-SpO2 responses in preterm infants are investigated. The model consists of a respiration and circulation submodule, interconnected by a pulmonary gas exchange submodule. Literature-based parameter ranges are provided. The model's ability to reproduce a patient's FiO2-SpO2 response, be generalised to different FiO2-SpO2 responses, and replicate physiological shunting and apnea scenarios is investigated. FiO2-SpO2 responses in preterm infants exhibit high variability and few responses are found stable. The model could be calibrated to specific FiO2-SpO2 responses using literature-based parameter ranges and could replicate physiologically expected shunting and apnea scenarios. The calibrated model could not be generalised to another FiO2-SpO2 response. The developed model for oxygen transport in preterm infants is a useful, modular, well-documented framework that can be used to develop and evaluate automated oxygen controllers.