Vascular ultrasound incorporates the Doppler principle to evaluate a wide spectrum of vascular disorders, including thrombosis, dissections, and aneurysms. The vascular system is well suited for evaluation by ultrasonography. The fluid-filled vessels are anechoic and easily visualized. Compressibility or variations in respiration may yield valuable information about the patency of a particular vessel. Vascular disorders may be uncovered in asymptomatic patients or in those presenting with hemorrhagic shock. Prompt diagnosis begins with a high index of suspicion and a thorough history and physical examination, and often requires an appropriate imaging study to confirm or refute a particular diagnosis. Ultrasonography is the screening tool of choice for a wide array of vascular disorders because of its safety, reliability, and ease of performance.