To evaluate whether the shock index (SI), given by the formula SI = heart rate/systolic blood pressure (HR/SBP), is useful for predicting mortality at 24 h in trauma patients admitted to the emergency department of a university hospital in Colombia. A database of trauma patients admitted between January 2013 and December 2013 was constructed; the result according to the shock index was determined, generating a dichotomous variable with two groups: Group A (SI < 0.9) and Group B (SI > 0.9). Univariate analysis was performed. A total of 666 patients were analyzed, 83.3% (555) had SI < 0.9, and 16.7% (111) SI > 0.9. The mean age for Groups A and B was 32.4 and 35.4 respectively. The average injury severity score for both groups was 9.6 and 17.6 respectively. Mortality at 24 h after injury for both groups was 3.1% (P = 0.032) and 59.5% (P = 0.027) respectively. An initial shock index greater than 0.9 implies a worse prognosis 24 h after injury. The shock index predicts mortality in multiple trauma patients in the emergency department, and is also a quick and applicable in all hospital.