Peripheral arterial disease (PAD) is a term implying obstruction of blood flow to lower or upper extremities, commonly caused by atherosclerosis, embolism, thrombosis, vasculitis, fibromuscular dysplasia, etc. In this chapter PAD and acute limb ischemia is discussed in detail along with its epidemiology, history, clinical presentation (symptoms, physical findings and ankle-brachial index), imaging studies, management. Acute limb ischemia is any sudden decrease in limb perfusion causing a potential threat to limb viability. Commonly used imaging modalities are duplex ultrasound, MR angiography, CT angiography and conventional angiography. There are two main goals of management i.e. prevention of myocardial infarction, stroke, and deaths; and treat leg symptoms and prevent amputation.