In this study the waste tire rubber was converted to carboxylated rubber without needed to reclaimed the rubber. Active carboxylate moieties were incorporated to the rubber chains of the wasted tire directly. Three types of active materials were used for the reaction with the wasted rubber; maleic anhydride, N-(2,5-dimethoxyphenyl) maleimic acid and N-(3carboxyphenyl) maleimic acid. The reaction was carried out by mixing the materials in closed system. The effect of feed ratio, time and the temperature of the reaction have been studied. It was noticed that increasing the time of reaction or the reaction increase the ratio of the reacted maleic anhydride or maleimic acid with the waste rubber. The optimum conditions for the reaction of maleic anhydride are more difficult than the reaction of maleimic acids. It was seen that period of time needed to get high reaction efficiency of maleic anhydride are 60min, at 220 0 C, while maleimic acids are more efficient in reaction with the waste rubber