Lower extremity peripheral artery disease (PAD) is the third leading cause of atherosclerotic cardiovascular morbidity, following coronary artery disease and stroke. PAD can present in several different ways and may include patients who are completely asymptomatic, or who have intermittent claudication, atypical symptoms during walking or critical limb ischaemia, or who may have had an amputation. This chapter describes the incidence and prevalence of different clinical manifestations, global distribution and future trends.