Post‐mortem human subjects with pre‐existing rib fractures are typically excluded from impact studies with the assumption that the fractures will alter thoracic response to loading. Given that the number of pre‐existing rib fractures required to alter thorax response is unknown, this study aimed to use the Global Human Body Models Consortium 50 th percentile whole‐body finite element model to explore the influence of pre‐existing fractures on thorax response to lateral loading. Up to six pre‐existing fractures were simulated on the anterior or lateral rib regions, and the model was subjected to a flat‐wall, lateral impact at initial speeds of 6.7 m/s or 8.9 m/s. Models with up to three pre‐existing fractures on the impacted and/or unimpacted ribs had similar thoracic response as the baseline model with no pre‐existing fractures. Conversely, models with pre‐ existing fractures on ribs 2‐7 of either the impacted or unimpacted ribcage exhibited changes in kinematics, increased rib strains, and/or decreases in chest deformations. The observed changes, however, were small relative to mid‐size male target response corridors for the loading condition simulated. The results therefore suggest that post‐mortem human subjects with pre‐existing fractures on up to three ribs may be appropriate for use in lateral impact testing.