Diethyl (acryloyloxy) ethylthiophosphoramidate (DEAETPN), a novel phosphorus-, nitrogen-, and sulfur-containing monomer, was synthesized in a two-step reaction. The monomer was polymerized and grafted onto cotton fabric by gamma radiation method. Effect of methyl methacrylate (MMA) on percentage grafting (Pg) of DEAETPN on cotton fabric was studied, and it was found that small amount of MMA increases Pg on cotton fabric. The monomer, polymer, and the grafted cotton fabric were characterized by spectroscopic and thermogravimetric techniques. Flame retardant property of the modified cotton fabric was studied by the Shirley Manual Flammability Tester. The flame retardancy of cotton-g-DEAETPN by gamma radiation method and living radical polymerization method was compared. (c) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012