Hypothesis: A growing proportion of urban trauma mortality is characterized by devastating and likely nonsurvivable injuries. Design: Consecutive samples from prospectively collected registry data. Setting: University level I trauma center. Patients: All trauma patients from January 1, 2000, to March 31, 2005. Main Outcome Measures: Data for trauma patients, including locale of death and mechanism of injury, comparing early (years 2000 through 2003) and late (2004 and 2005) periods. Results: A total of 11 051 trauma visits were registered during the study period with 366 deaths for an overall mortality of 3.3%. Penetrating injury occurred in 26.7% of patients; however, 71.9% of trauma mortalities (263 patients) died with penetrating injuries. Of the patients who died, 48.3% demonstrated severe penetrating injuries (Abbreviated Injury Score ≥4) to the head while 32.7% presented with severe penetrating chest injuries. There was a significant increase in the mortality rate over time (3.0% [early] vs 4.3% [late], P<.01). In parallel, emergency department mortality (patients dead on arrival and those not surviving to hospital admission) increased from 1.7% to 3.1% (P<.005), yet postadmission mortality remained constant (1.3% [early] vs 1.2% [late], P=.77). When emergency department mortality and the subsequent hospital mortality of patients with gunshot wounds to the head were combined, this represented 82.6% of all trauma mortalities in the late period. This was increased from 69.7% during the early period (P<.01). Conclusions: While in-hospital mortality has remained the same, the proportion of nonsurvivable traumatic injuries has increased. In a mature trauma system, this provides a compelling argument for violence prevention strategies to reduce urban trauma mortality.