Atherosclerosis is the hardening and thickening of arteries due to plaque buildup within the arterial wall. It is caused by an inflammatory response to injury and risk factors such as high cholesterol, hypertension, smoking, and diabetes. The pathogenesis involves monocytes migrating into the damaged artery and oxidized LDL cholesterol building up in macrophages to form foam cells, which accumulate to create fatty streaks and fibrous plaques that can restrict blood flow. Diagnosis relies on physical exams, imaging tests, and blood tests. Treatment focuses on modifying risk factors through lifestyle changes and medications to lower cholesterol and blood pressure. Current research is exploring new biomarkers for detection and treatments to improve vascular function and reduce cardiovascular events.