Glycosaminoglycans (GAGs) take part in numerous biological processes by binding to protein molecules and functionally regulating protein-ligand interactions; therefore, molecular interactions of GAGs have been studied by several methods, including surface plasmon resonance, enzyme-linked immunosorbent assays (ELISAs), and GAG microarrays. To achieve rapid, sensitive, and high-throughput screening of GAG interactions, we have developed a novel microarray in which GAGs, including chondroitin sulfate, heparan sulfate, and heparin, were immobilized. The microarray is made from cyclic polyolefin substrate coated with metacrylate polymers, which have phospholipid groups as side chains. The polymer also has aminooxy groups that react specifically with aldehyde groups at the reducing termini of GAG chains, whereas the phospholipid groups prevent nonspecific adsorption of proteins. Thus, minute amounts of GAGs can be chemically immobilized on the surface with low nonspecific binding of proteins. Using this array, interactions between GAGs and antibodies against chondroitin or heparan sulfate and heparin-binding growth factors were examined. The results were in agreement with previously reported specificities, suggesting that the GAG array is useful for high-throughput interaction analyses between GAGs and functional proteins in miniscule amounts and can be applied to both basic studies of GAGs and the development of diagnostic methods for metabolic diseases involving GAGs