In this research the activated carbons were prepared from rice straw, rice husk shelland sugarcane bagasse using a chemical activation method by impregnation with H3PO4at identical optimum conditions: activation temperature of 600 oC, activation agent toraw material ratio of 1:1 and activation time of 60 minutes. The derived activated carbonswere then analyzed for the composition by proximate analyses and the adsorption capacityof iodine and methylene blue. In addition, Freundlich adsorption isotherms of theadsorption capacity of iodine and methylene blue were investigated. The results showedthat the activated carbon obtained from rice straw yielded the highest iodine adsorption(Iodine number), 998 mg/g. The activated carbon obtained from rice husk shell showedthe highest methylene blue adsorption, 305 mg/g. When compared to the two commercialactivated carbons, the activated carbon obtained from rice straw had an iodine adsorptioncapacity close to the second commercial activated carbon, but less than the first one.While the methylene blue adsorption capacity of the activated carbon obtained fromthose three experimental materials had lower levels compared to the two commercialactivated carbons. However, the activated carbons obtained from rice straw, rice husk shelland sugarcane bagasse still showed the good qualities to use as activated carbon becauseall iodine numbers are more than 600 mg/g and the moisture contents (%) are less than8%, the standards considered by the TISI.900-2547.