This study describes preparation of poly (acrylic acid)-grafted cotton fibers and release of antibiotic drug gentamicin sulfate from them under physiological conditions. Poly(acrylic acid) has been grafted onto cellulose backbone of cotton fibers via Ce(IV)-initiated polymerization in aqueous medium. The conditions obtained for optimum grafting were as follows: initiation time 30 min; initiation temperature 37 degrees C; monomer concentration 27.8 mM; grafting temperature 30 degrees C; nitric acid (catalyst) concentration 0.1M. The grafted fibers were characterized by FTIR, TGA, and SEM analysis. The antibiotic drug gentamicin sulfate (GS) was loaded into the grafted fibers by equilibration method and release was studied under physiological conditions. The kinetic release data was interpreted by first-order kinetic model. Finally, drug-loaded fibers showed fair antibacterial action against Escherichia coli. (c) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122: 366-374, 2011