Matrix metalloproteinases (MMPs) have a great variability that provides a complex intervention in pathophysiological conditions. MMPs roles in pathology may be grouped into the following main types: (1) tissue destruction, as in cancer invasion and metastasis, rheumatoid arthritis, osteoarthritis, different types of ulcers, periodontal disease, brain injury and neuroinflammatory diseases; (2) fibrosis, as in liver cirrhosis, fibrotic lung disease, otosclerosis, atherosclerosis, and multiple sclerosis; (3) weakening of matrix, as in dilated cardiomyopathy, epidermolysis bullosa, aortic aneurysm and restenotic lesions. Recent data also adds new MMPs functions in angiogenesis and apoptosis. Interesting opposite intervention in escaping mechanisms vs. antitumor defensive mechanisms had been also reported. As MMP-7 is expressed by tumor cells of epithelial and mesenchymal origin, it may be used as a biological marker of an aggressive phenotype and as a target of therapeutic intervention. MMPs play a pivotal role in the pathogenesis of arthritis, atherosclerosis, pulmonary emphysema, and endometriosis. Although MMP involvement in pathology is more than simple excessive matrix degradation, or an imbalance between them and their specific tissular inhibitors (TIMPs), MMP inhibition may be of therapeutic benefit, so synthetic MMPs inhibitors had been developed and are currently under clinical testing.