Activated carbon from Cocos nucifera leaves agrowaste was derived. The effect of impregnation ratio was studied by chemical activation method using phosphoric acid as an activating agent. Activated carbon was produced at the activation temperature of 673 K by slow pyrolysis. Nitrogen adsorption isotherms study was performed. Effect of impregnation ratio on the yield, methylene blue number, iodine number, and acid adsorption was studied. The FT-IR spectra show the presence of activated carbon. The TGA investigation reveals that activated carbon is thermally stable at 723 K.