The grafting of acrylic acid (AA) onto polypropylene (PP) nonwoven fabric was induced by gamma-ray irradiation without degassing to obtain PP-g-AA-modified nonwoven fabric. Chitosan was immobilized onto the PP-g-AA-modified nonwoven fabric with 1-ethyl-3-(3-dimethyamino propyl) carbidiimide to get the chitosan-containing PP-g-AA-modified nonwoven fabric. The PP-g-AA-modified nonwoven fabrics were characterized by IR spectroscopy. In addition to the absorption peaks associated with pure PP nonwoven fabric, absorption peaks at 1700 cm(-1) (C=O) and at about 2950 cm(-1) for the COOH group were also found for the PP-g-AA-modified nonwoven fabric. The chitosan-containing PP-g-AA nonwoven fabric obtained had an absorption peak at about 1475-1580 cm(-1) (CO-NH), in addition to those of the PP-g-AA nonwoven fabric. The effects of acrylic acid grafting content and chitosan on the wettability and antibacterial assessment were investigated. The wicking time of water on the PP-g-AA-modified nonwoven fabric decreased with increasing acrylic acid grafting content and chitosan, whereas the water content on the PP-g-AA-modified nonwoven fabric increased. Because the concentration of Pseudomonas aeruginosa on the PP-g-AA-modified nonwoven fabric decreased with increasing acrylic acid grafting content and chitosan, it means that the antibacterial activity of the PP nonwoven fabric was enhanced by the modification of gamma-ray radiation-induced grafting of acrylic acid and the immobilization of chitosan onto the PP-g-AA-modified nonwoven fabric. (C) 2003 Wiley Periodicals, Inc.