The effects of dual responses [Basic Life Support (BLS) and Advanced Life Support (ALS)] on the outcomes of trauma patients were evaluated. Outcomes included changes in physiologic measurements between the scene and the emergency department (ED), and survival to hospital discharge. Data for 2394 patients with penetrating, motor vehicle crash (MVC), or other blunt injuries were included. Changes in physiologic measurements (Revised Trauma Scores) between the prehospital and ED settings were positively associated with documented ALS or dual response care. Survival to hospital discharge among penetrating injury patients was negatively related to dual responses, whereas that among MVC patients was positively associated with dual responses. Parallel results were found for a subset of more severely injured patients. Future research should confirm and refine these results so that protocols for the appropriate use of dual response runs can be developed.