Matrix metalloproteinases (MMPs), a family of proteolytic enzymes that degrade extracellular matrix (ECM), seem to have an important role in pathogenesis of atherosclerosis. Released by inflammatory cells and smooth muscle cells, MMPs regulate the vascular remodeling process. The expression and activity of MMPs is regulated at the level of transcription by a variety of cytokines, proenzyme activation by several cellular and serum proteases, as well as by endogenous and exogenous inhibitors. Overproduction of MMPs could promote arteriosclerosis, leading to atherosclerotic plaque formation, and plaque rupture, resulting in clinical consequences such as myocardial infarction, or critical limb ischemia. Increased plasma levels of some MMPs are now regarded as potential biomarkers of atherosclerosis and cardiovascular risk. The potential significance of MMP inhibitors in atherosclerosis therapy is discussed.