Methacrylamide (MAam) as a reactive monomer was directly grafted onto cotton yarns using a KMnO4 -HNO3 redox system by chemical initiation technique. The major factors affecting polymerization of MAam, such as KMnO4, nitric acid and MAam concentration as well as the reaction time (duration) and temperature of the polymerization were studied. This was done to establish the optimum conditions of grafting. It was found from the results that the graft yield is higher under the following conditions: using 0.07 N potassium permanganate as initiator, 80 meq L-1, nitric acid; 1 g, methacrylamide, reaction time, 60 min and polymerization temperature, 60 ° C, when using a material to liquor ratio of 1:50. On the other hand, the tensile strength of poly (MAam)-cotton yarn grafts copolymer having 18.55% graft yield exhibits a higher value than ungrafted cotton yarn. While, increasing the graft yields over 18.55% lead to a decrease in tensile strength of the grafted yarn.