The extracellular matrix (ECM) is a framework of proteins and proteoglycans, secreted by and surrounding stromal fibroblasts. The ECM gives structural integrity to tissues. Remodelling of the ECM is essential for both tumour invasion and angiogenesis. There is abundant evidence to suggest that ECM degrading enzymes, including matrix metalloproteinases (MMPs), are involved in these processes. MMPs are novel targets for therapeutic intervention with the potential to inhibit tumour growth and invasion either on their own or in conjunction with cytotoxic treatments. This review outlines our current understanding of the regulation of MMP expression, the association of MMPs with tumour growth, invasion and angiogenesis and the clinical evolution of MMP inhibitors.