Vascular ultrasound provides an effective and noninvasive screening method to evaluate various types of vascular diseases at the bedside. Vascular processes can often have very subtle symptoms initially but quickly progress to devastating and life-threatening conditions. Therefore, vascular ultrasound provides clinicians with a valuable tool to help screen for these hard-to-diagnose conditions early in their clinical presentation. Vascular ultrasound encompasses the evaluation of superficial and deep veins, peripheral arteries, carotid arteries, pseudoaneurysms, and procedural access. In this chapter, we will discuss the principles of vascular ultrasound while focusing on its most common POCUS applications.