Certain extremity injuries presenting to the ED or Trauma Unit warrant increased suspicion for underlying arterial trauma. Such injuries include knee dislocations, displaced medial tibial plateau fractures and other displaced bicondylar fractures around the knee, open or segmental distal femoral shaft fractures, floating joints, gunshot wounds in proximity to neurovascular structures, or mangled extremities. Once the diagnosis of arterial trauma is made, a multi-disciplinary approach is warranted. The diagnostic strategies for vascular injury have undergone an evolution over the past 2 decades. One and a half percent to 4.6% of patients hospitalized with blunt extremity trauma have associated vascular compromise [Bunt TJ, Malone JM, Moody M, et al. Am J Surg 1990;160(2):226-8; Reid JD, Weigelt JA, Thal ER, et al. Arch Surg 1988;123(8):942-6; Applebaum R, Yellin AE, Weaver FA, et al. Am J Surg 1990;160(2):221-4; discussion 224-5; Dennis JW, Frykberg ER, Veldenz HC, et al. J Trauma 1998;44(2):243-52; discussion 242-3]. An efficient and effective evidence-based approach to diagnosing vascular injury is necessary, as the difficulty in diagnosis, the multiplicity of diagnostic strategies, the limited time frame in which to initiate appropriate treatment, the limb threatening complications of a missed diagnosis, and the increased awareness of health care expenditures make this entity an intimidating diagnostic challenge [Johansen K, Lynch K, Paun M, et al. J Trauma 1991;31(4):515-9; discussion 519-22; Lynch K, Johansen K. Ann Surg 1991;214(6):737-41; Walker ML, Poindexter Jr JM, Stovall I. Surg Gynecol Obstet 1990;170(2):97-105; Kendall RW, Taylor DC, Salvian AJ, et al. J Trauma 1993;35(6):875-8]. The purpose of this article is to present an evidence-based algorithm for patients who present with either arterial injury or a high-risk of arterial injury. A diagnostic algorithm will be presented, and the rationale for diagnostic interventions will be discussed in the context of current medical literature.