The extracellular matrix is a diverse composition of glycoproteins and proteoglycans found in all cellular systems. The extracellular matrix, abundant in the mammalian central nervous system, is temporally and spatially regulated and is a dynamic“living”entity that is reshaped and redesigned on a continuous basis in response to changing needs. Some modifications are adaptive and some are maladaptive. It is the maladaptive responses that pose a significant threat to successful axonal regeneration and/or sprouting following traumatic and spinal cord injuries, and has been the focus of a myriad of research laboratories for many years. This review focuses largely on the extracellular matrix component, chondroitin sulfate proteoglycans, with certain com-parisons to heparan sulfate proteoglycans, which tend to serve opposite functions in the central nervous system. Although about equally as well characterized as some of the other proteoglycans such as hyaluronan and dermatan sulfate proteoglycan, chon-droitin sulfate proteoglycans are the most widely researched and discussed proteoglycans in the ifeld of axonal injury and regen-eration. Four laboratories discuss various aspects of chondroitin sulfate proteoglycans and proteoglycans in general with respect to their structure and function (Beller and Snow), the recent discovery of speciifc chondroitin sulfate proteoglycan receptors and what this may mean for increased advancements in the ifeld (Shen), extracellular matrix degradation by matrix metallopro-teinases, which sculpt and resculpt to provide support for out-growth, synapse formation, and synapse stability (Phillips et al.), and the perilesion microenvironment with respect to immune system function in response to proteoglycans and central nervous system injuries (Jakeman et al.).