In this study the waste tire rubber was converted to carboxylated rubber without needed to reclaimed the rubber. An 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-(3,5-dimethoxyphenyl) maleimic acid and N-(3-carboxyphenyl) 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.