Matrix metalloproteinases (MMPs), also known as matrixins are endoproteinases that degrading protein components of the extracellular matrix (ECM), cause its restoration and reconstruction. In this way, retain the appropriate structure of the ECM and basement membrane during both: physiological processes and pathological conditions. Changes in the structure of the ECM are accompanied by physiological processes such as embryogenesis, angiogenesis, apoptosis, and development and rebuilding of connective tissue. Under physiological conditions, the activity of MMPs is regulated at the transcriptional level, activation of proMMP precursor zymogens and interactions with endogenous inhibitors (tissue inhibitors of metalloproteinases, TIMPs). The imbalance in the system of MMPs/TIMPs induces the development of many diseases, including cancer, fibrosis, arthritis, cardiovascular diseases, neurological and autoimmune disorders. The publication describes the types of metalloproteinases, their structure, function and regulation of activity and endogenous inhibitors of MMPs.