A series of six disaccharides, alpha-L-IdoA-(1-->4)-alpha-D-GlcNAc-1-->OMe alpha-L-IdoA-(1-->4)-alpha-D-GIcNSO(3)-1-->OMe, beta-D-GlcA-(1-->4)-alpha-D-GlcNAc-1-->OMe, beta-D-GlcA-(1-->4)-alpha-D-GlcNSO(3)-1-->OMe, alpha-D-GlcNAc-(1-->4)-beta-D-GlcA-1-->OMe, beta-D-GlcNAc-(1-->4)-beta-D-GlcA-1--->OMe, and two trisaccharide, beta-D-GlcA-(1-->4)-alpha-D-GlcNAc-(1-->4)-beta-D-GlcA.1-->OMe, alpha-L-IdoA-(1-->4)-alpha-D-GlcNSO(3)-(1-->4)-beta-D-GlcA-1-->Ome was prepared and screened for biological activity in vitro. The oligosaccharides were tested, togetherwith a previously synthesized trisaccharide, alpha-L-IdoA-(1-->4)-alpha-D-GlcNAc-(1-->4)-beta-D-GlcA-1-->Ome, and three tetrasaccharides, alpha-L-IdoA-(1-->4)-alpha-D-GlcNAc-(1-->4)-beta-D-GlcA-(1-->3-beta-D-Gal-1-->Ome, beta-D-GlcA-(1-->3)-beta-D-Gal-(1-->3)-beta-D-Gal-(1-->3)020PO(3)-beta-D-Xyl-1-->Ome, beta-D-GlcA-(1-->3)-beta-D-Gal-(1-->3)-beta-Gal-(1-->3)-beta-D-Xyl-1-->Ome, for competitive binding to acidic and basic fibroblast growth factor in an assay using I-125 labelled heparin. It was found that the non-sulphated trisaccharides, alpha-L-IdoA-(1-->4)-alpha-D-GlcNAc-(1-->4)-beta-D-GlcA-1-->OMe and beta-D-GlcA-(1-->4)-alpha-D-GlcNAc-(1-->4)-beta-D-GlcA-1-->OMe, and two of the disaccharides can bind to acidic as well as basic FGF.