The graft copolymerization of acrylonitrile onto cotton, initiated by the KMnO4-thioacetamide redox system in an aqueous medium, has been investigated. The percentage graft yield was determined by varying the concentrations of KMnO4, acrylonitrile, thioacetamide, and temperature. The percentage graft yield increased initially and then decreased with increasing concentrations of KMnO4 and thioacetamide, with an optimum yield not greater than 21%. The percentage graft yield, however, was greatly enhanced with a value of up to 66% as the concentration of acrylonitrile was increased. The percentage graft yield increased with temperature in the range of 35-70-degrees-C with a calculated activation energy of 8.33 Kcal/mol. The effects of solvents and amines on the percentage graft yield were also investigated.