Matrix metalloproteinases (MMPs) are a family of proteolytic enzymes important in the degradation and turnover of extracellular matrix (ECM) components. MMPs and their inhibitors play major roles not only in ECM degradation but also in mediating cell-cell adhesion, cell migration and invasion, cell proliferation and apoptosis, tissue remodeling, and growth factor and cytokine signaling. There is a vast amount of literature regarding changes in MMPs and MMP inhibitor levels during the progression of cardiovascular diseases but a paucity of information regarding their roles in the embryonic cardiovascular development. Yet, by studying cardiovascular development, much can be learned with regard to the pathophysiology and etiology of adult cardiovascular diseases. In fact, the development of many pathological conditions may reflect inappropriate recapitulation of embryonic events. The objective of this review is to provide an overview of what is known regarding the role of MMPs and their inhibitors during embryonic cardiovascular development and to relate these to the pathophysiology of adult cardiovascular diseases whenever possible.