Extracellular matrix macromolecules regulate cell shape through specific interactions with receptors: thus cell-matrix interactions have a significant role in directing cell growth, gene expression, and cell differentiation. Matrix proteins typically promote cell attachment, spreading, and cytoskeletal organization. In addition, there is a group of extracellular matrix proteins that are primarily anti-adhesive, rather than adhesive. These proteins, thrombospondin (TSP), tenascin, and SPARC, induce a loss of focal adhesions from spread endothelial cells with accompanying cytoskeletal changes characterized by a cortical redistribution of stress fibers and a dispersal of vinculin from adhesion plaques. The temporally- and spatially-restricted expression of these proteins in injured and developing tissues is consistent with their anti-adhesive properties. The interactions of these proteins with cells has potentially important consequences for cell migration, wound healing, and tumor cell metastasis. The anti-adhesive matrix proteins are thought to mediate these effects via interactions with receptors and generation of intracellular messengers rather than by physical disruption of cell-matrix interactions, as evidenced by the retention of the αvβ3 in adhesion plaques. In this review, the structural and functional characteristics of the anti-adhesive matrix proteins, their effects on adhesion and cytoskeletal organization, the active sites of these molecules and their putative receptors, and the influence of glycosaminoglycans on their activity will be discussed. © 1995, FCCA(Forum: Carbohydrates Coming of Age). All rights reserved.