The properties and characterization of a novel series of amphoteric polypropylene fabrics were done by gamma-preirradiation followed by grafting methacrylic acid and then amination using (3-chloro-2-hydroxyl propyl)ammonium derivatives. The new amphoteric grafted PP fabrics have an increase in moisture regain up to 5.5% and100% reduction in growth of Staphylococcus aureus and Klebsiella pnemnonia. Also, the dyeability was improved using acid and basic dyes. These new amphoteric textiles properties were studied using differential scanning calorimetry (DSC) and thermogravimetric analysis including TGA and DTA. A slight decrease in the crystallinity was observed by DSC and X-ray diffraction. The modified PP fabrics can be used for the development of upholstery and medical fabrics with antimicrobial properties. (c) 2005 Wiley Periodicals, Inc.