A cationic functionalization was carried out on poly(ethylene terephtalate) (PET) nonwovens by the method of padding with a solution of polymer (P1 and Px). An atmospheric pressure plasma treatment was prior used to improve the hydrophilic property of the nonwoven surface before the functionalization with cationic agents. The zeta potential measurements of the nonwovens, based on streaming potential, show the presence of cationic groups at the PET surface depending on the pH value. The analysis of washing water showed that the PET nonwoven functionalized with cationic polymer Px needed more washing cycles than with polymer P1, to remove all the species non fixed at the surface. The cytotoxicity tests show that both of ammonium polymers are toxic toward endothelial cells. This means that it leaves many active chemicals on the surface of the functionalized materials, even after washing. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012