The objective of this research was the surface grafting polymerization of biocompatible monomer N-vinyl-2-pyrrolidone (NVP) onto a plasma-treated nonwoven poly(ethylene terephthalate) (PET) substrate with ultraviolet (UV)-induced methods. The effects of various parameters, such as the monomer concentration, reaction time, initiator (ammonium peroxodisulfate) concentration, and crosslinking agent (N,N'-methylene bisacrylamide) concentration, on the grafting percentage were studied. The grafting efficiency of the modified nonwoven PET surfaces reached a maximum at 50 min of UV irradiation and with a 30 wt % aqueous NVP solution. After the plasma activation and/or grafting, the hydrophobic surface of the nonwoven was modified into a hydrophilic surface. NVP was success-fully grafted onto nonwoven PET surfaces. The surface wettability showed that the water absorption of NVP-grafted nonwoven PET (NVP-g-nonwoven PET) increased with increasing grafting time. NVP-g-nonwoven PET was verified by Fourier transform infrared spectra and scanning electron microscopy measurements. An antibacterial assessment using an anti-Staphylococcus aureus test indicated that S. aureus was restrained from growing in NVP-g-nonwoven PET. (c) 2006 Wiley Periodicals, Inc.