Cyanoxyl persistent radicals can be used as chain-growth moderators of the statistical copolymerization of a variety of monomers. We report herein the preparation of fully sulfated lactose-based glycopolymers by cyanoxyl ((.)OCequivalent toN)-mediated free-radical polymerization of acrylamide derivatized glycomonomers in good yield (60-80%) and low polydispersity (1.1 < M-w/M-n < 1.6). Prolongation of the activated partial thromboplastin time (aPTT) was observed, and structure-activity relationships were defined. Specifically, the anticoagulant effect varied in response to both polymer molecular weight and the density of pendant sulfated lactose units. Nonetheless, measured thrombin times were only modestly prolonged suggesting that the observed anticoagulant effect is not primarily related to direct thrombin inhibition.