Grafting of the mixture of acrylamide and acrylic acid onto polyester and polypropylene fibers and mixture of acrylic acid and methacrylic acid onto polypropylene by the radiation method are reported. It is observed that when pure acrylamide was used for grafting, the grafting extent was small, whereas when the mixture was used, the amount of acrylamide content in the copolymer was found to be more than the feed ratios. The results are explained on the basis of chain transfer mechanism. With methacrylic acid and acrylic acid mixtures, the rate of grafting decreased with the increase in the concentration of acrylic acid in the feed ratio, and this has been explained on the basis of the formation of either a 3-dimensional network structure or a highly branched structure involving backbone polymer molecules with acrylic acid, which prevents the diffusion of the monomer from the solution phase to the swollen phase.