The diagnosis of peripheral vascular trauma has undergone significant evolution in the last two decades. A minority of patients with arterial trauma present with classic findings that make the diagnosis obvious. However, the diagnosis of occult arterial injuries is more challenging, and it is for this group that the diagnostic algorithm has changed most significantly. Because of the low yield of routine operative exploration and routine arteriography to evaluate potential injury to vessels in proximity to penetrating wounds, many authors now recommend the selective use of arteriography or other diagnostic modalities based on the results of clinical examination and noninvasive pressure determinations. This article reviews the evidence in support of such a selective approach to the diagnosis of arterial injuries.