Background: An assessment of hemodynamic stability is central to surgical decision-making in the management of battlefield ballistic torso trauma (BBTT). Aims: To analyse the utility of admission physiological parameters in characterising hemodynamic stability. Settings and Design: A retrospective analysis of consecutive admissions, with BBTT, to forward surgical facility in Afghanistan. Materials and Methods: The cohorts' admission physiology, need for operative intervention, and mortality data were collected retrospectively. The cohort was divided into patients requiring surgery for Life-Threatening Torso Hemorrhage (LTTH) and those not requiring immediate surgery (non-LTTH). Statistical Analysis: Parameters were compared using two sample t tests, Mann-Whitney, Fisher's exact, and Chi-square tests. Receiver operator characteristic curves were used to identify significant parameters and determine optimum cut-off values. Results: A total of 103 patients with isolated BBTT were identified: 44 in the LTTH group and 59 in the non-LTTH group. The mean New Injury Severity Score ± Standard Deviation (NISS±SD) was 28±14 and 13±12, respectively. The heart rate, systolic blood pressure (SBP), pulse pressure, shock index (SI=heart rate/SBP) and base excess were analysed. SI correlated best with the need for surgical torso hemorrhage control, P<0.05. An optimal cut-off of 0.9 was identified, producing a positive and negative predictive value of 81% and 82%, respectively. Conclusions: Shock index (SI) is a useful parameter for helping military surgeons triage BBTT, identifying patients requiring operative torso hemorrhage control. SI performance requires a normal physiological response to hypovolemia, and thus should always be considered in clinical context.