Acute limb ischemia (ALI) is a serious condition that can threaten the limb's viability and the patient's life. It is usually caused by atherosclerotic disease but can also arise from nonatherosclerotic causes. It has numerous clinical manifestations, the most common of which is pain. Proper diagnosis involves history, physical examination, and techniques such as Doppler assessment, contrast-enhanced magnetic resonance angiography, or catheter-based angiography. Differential diagnosis is important, as many other conditions can mimic ALI. Ischemia severity can be classified into three levels: viable; threatened, either marginally or immediately; and irreversible. Treatment options include surgical and less invasive endovascular techniques. Prognosis can be excellent, and early diagnosis and prompt initiation of therapy are essential to achieving a good outcome.