Over recent years a number of cartilage and bone matrix molecules have been identified and characterized. These include major constituents such as collagens and proteoglycans as well as a number of less-abundant matrix proteins. In several cases these proteins have been characterized by cloning and sequence analysis of the corresponding cDNA. Some properties of the macromolecules have been studied and an understanding of their functions in the structure, assembly, and breakdown of connective tissue matrix is emerging. It appears that some of these molecules have structural roles whereas others participate in the assembly of the tissue. In this paper we attempt to give a current picture of the organization and role of the noncollagenous matrix macromolecules in cartilage and bone.