Most patients with lower extremity peripheral arterial disease (PAD) are asymptomatic. Although intermittent claudication is the classic presenting symptom in those who are symptomatic, PAD often presents atypically as a result of associated comorbidities. The differential diagnosis involves consideration of many nonvascular and nonatherosclerotic causes of exercise-associated leg pain. Weak or absent pulses are the hallmark physical finding of PAD, and the ankle-brachial index is the most efficient objective test for documenting it. PAD may progress to acute limb ischemia (acute deterioration of limb flow) or critical limb ischemia (chronic compromise in limb perfusion which resulting in rest pain and tissue loss), both of can lead to limb loss without timely treatment.