Objective. Traumatic diaphragmatic injuries (TDI) are uncommon but associated with substantal morbidity and mortality. We sought to analyze patients with TDI at a large trauma center and associated county coroner to identity characteristics preditive increased mortality. Methods. We queried a level I nonversity trauma center and associated county coroner databases containing > 20,000 patients to identify patients with ICD-9 diagnoses pertaining to TDI from January 1992 through May 2005. Once identified, hospital records, operative details, and autopsy reports were reviewed to determine injury characteristus, beatment provided, and outcome. Statistical analyses were performed using the Student t-test, chu-square analysis, analysis of variance, and multiple logistic regression. Results. TDI were identified in 254 individuals. Two hundred (79%) survived to undergo operation. Of the 81 (32%) deaths, 33 (41%) occurred before arrival at the trauma center: Survivors were younger, had lesser injury severity scores (ISS), were more likely to be female, and had more bilateral injuries (P <= .002 all) than nonsurvivors. By multiple logistic regression analyses, increased age (odds ratio [OR], 1.044; 95% confidence interval [CI], 1.015-1.074; P = .0029) and greater ISS (Or, 1.145; 95% CI, 1.103-1.188, P < .0001) were predictors of the probability of death in all patients. Conclusion. Although TDI may indicate substantive trauma burden in any patient, those with greater ISS and advanced age are at the greatest risk of death. (Surgery 2009;146.578-84)