Cyclophilin A (CyPA) is a 17 kDa, ubiquitously expressed multifunctional protein that possesses peptidylprolyl cis-trans isomerase activity and scaffold function. Its expression is increased in inflammatory conditions including rheumatoid arthritis, autoimmune disease and cancer. Intracellular CyPA regulates protein trafficking, signal transduction, transcription regulation and the activity of certain other proteins. Secreted CyPA activates cardiovascular cells resulting in a variety of cardiovascular diseases; including vascular remodeling, abdominal aortic aneurysms formation, atherosclerosis, cardiac hypertrophy and myocardial ischemic reperfusion injury. (J Korean Soc Hypertens 2011;17(4):133-147)