The modification of polypropylene fibres (POP) and POP fleece prepared by preirradiation technique is discussed. Grafting measure, hydrophility change and dyeing ability of the radiation modified samples were studied. The preirradiation and the simultaneous one were performed in a chamber type RCH-gamma-30 radiation equipment, having the emitters charge of60Co. For radiation-induced grafting 5–30% acrylic acid solution was used. It was proved that the percentage of irradiation-induced grafting of both POP fibres and POP fleece increased with an increase in the radiation dose and the concentration of acrylic acid. Samples modified by this technique have a good dyeing ability and their dyeing intensity increased parallel with the percentage of grafting.