A sample of 360 severely injured patients was selected from a cohort of 8007 trauma victims followed prospectively from the time of injury to death or discharge. A case referent study was used to test the association between on-site care, total prehospital time, and level of care at the receiving hospital with short-term survival. Multiple logistic regression analyses showed that use of Advanced Life Support (ALS) at the scene was not associated with survival, whereas treatment at a level I compatible hospital was associated with a 38% reduction in the odds of dying, which approached statistical significance. Total prehospital time over 60 minutes was associated with a statistically significant adjusted relative odds of dying (OR = 3.0). The results of this study support the need for regionalization of trauma care and fail to show a benefit associated with ALS.