Vascular endothelial growth factor (VEGF) represents a target for antiangiogenic therapies in a wide spectrum of diseases, including cancer. As a novel strategy to generate nonanticoagulant antiangiogenic substances exploiting binding to VEGF while preventing receptor engagement, we assessed the VEGF-antagonist activity of a low-molecular-weight (LMW) compound (ST2184, Mw = 5800) generated by depolymerization of an undersulfated glycol-split heparin derivative. The parental compound was obtained by introducing regular sulfation gaps along the prevalently N-sulfated heparin regions, followed by glycol-splitting of all nonsulfated uronic acid residues (approximately50% of total uronic acid residues). ST2184 was endowed with a negligible anticoagulant activity after S.C. injection in mice. ST2184 binds VEGF₁₆₅ as evaluated by its capacity to retard ¹²⁵I-VEGF₁₆₅ electrophoretic migration in a gel mobility shift assay and to prevent VEGF₁₆₅ interaction with heparin immobilized onto a BIAcore sensor chip. Unlike heparin, ST2184 was unable to present ¹²⁵I-VEGF₁₆₅ to its high-affinity receptors in endothelial cells and inhibited VEGF₁₆₅-induced neovascularization in the chick embryo chorioallantoic membrane. Undersulfated, LMW glycol-split heparins may therefore provide the basis for the design of novel nonanticoagulant angiostatic compounds.