Blunt thoracic aortic injuries (BTAI) are traditionally treated as emergencies with most fixed within 24 hours of arrival by thoracic endovascular aortic repair (TEVAR) regardless of grade of injury. However, the optimal timing of repair remains debated. All patients with grade 2 and 3 BTAI enrolled in the Aortic Trauma Foundation prospective multi-center registry from 2015 to 2022 were categorized dependent on timing of repair (ER=Early Repair<24 hours, LR=Late Repair>24 hours). Chi-square/Fisher's exact tests were used to compare patient/operative factors and logistic regression analysis was performed to identify factors related to 30-day mortality. 222 Grade 2 and 3 BTAI treated by TEVAR were analysed, with 179 in the ER group (81%). There was no difference between the groups regarding Injury Severity Score (ISS), Glasgow Coma Scale (GCS), age, or gender. Those in ER were more likely to have a widened mediastinum and a shorter distance from the left subclavian artery to the injury. 30-day in-hospital mortality occurred in 14 patients (6%); 2 of which were aortic-related. 30-day mortality was associated with a higher baseline incidence of CAD/PVD/previous cardiac revascularisation; lower systolic blood pressure, GCS, hemoglobin, platelet count and blood pH; and higher lactate and ISS on arrival. On multivariate regression analysis, lower haemoglobin, higher ISS, and Grade 3 BTAI were associated with 30-day mortality (p<0.05), although time to TEVAR was not. In selected patients, delay in performance of TEVAR for Grade 2 & 3 BTAI may be possible. Further research is necessary to identify other factors predictive of success.