BACKGROUND Avoiding missed diagnosis and therapeutic delay for significant blunt bowel and mesenteric injuries (sBBMIs) after trauma is still challenging despite the widespread use of computed tomography (CT). Several scoring tools aiming at reducing this risk have been published. The purpose of the present work was to assess the incidence of delayed (>24 hours) diagnosis for sBBMI patients and to compare the predictive performance of three previously published scores using clinical, radiological, and laboratory findings: the Bowel Injury Prediction Score (BIPS) and the scores developed by Raharimanantsoa Score (RS) and by Faget Score (FS). METHODS A population-based retrospective observational cohort study was conducted; it included adult trauma patients after road traffic crashes admitted to Lausanne University Hospital, Switzerland, between 2008 and 2019 (n = 1,258) with reliable information about sBBMI status (n = 1,164) and for whom all items for score calculation were available (n = 917). The three scores were retrospectively applied on all patients to assess their predictive performance. RESULTS The incidence of sBBMI after road traffic crash was 3.3% (38 of 1,164), and in 18% (7 of 38), there was a diagnostic and treatment delay of more than 24 hours. The diagnostic performances of the FS, the RS, and the BIPS to predict sBBMI, expressed as the area under the receiver operating characteristic curve, were 95.3% (95% confidence interval [CI], 92.7–97.9%), 89.2% (95% CI, 83.2–95.3%), and 87.6% (95% CI, 81.8–93.3%) respectively. CONCLUSION The present study confirms that diagnostic delays for sBBMI still occur despite the widespread use of abdominal CT. When CT findings during the initial assessment are negative or equivocal for sBBMI, using a score may be helpful to select patients for early diagnostic laparoscopy. The FS had the best individual diagnostic performance. However, the BIPS or the RS, relying on clinical and laboratory variables, may be helpful to select patients for early diagnostic laparoscopy when there are unspecific CT signs of bowel or mesenteric injury. LEVEL OF EVIDENCE Prognostic and Epidemiological; Level III.