The extracellular matrix (ECM) is a vital component of connective tissue, and collagen is a major constituent. There is growing evidence that changes in the composition of the cardiac and vascular matrix occurs during hypertension. Clinically, these effects are manifested as left ventricular hypertrophy and a reduction in arterial compliance and luminal diameter, which results in end organ ischaemia. The matrix metalloproteinases and their inhibitors have a central role in the regulation of the composition of the ECM. In this review, we discuss the mediators that affect the structure of the ECM in hypertension using results from animal and human studies.