The aims of this study are to determine the influence of percentage of potassium hydroxide (KOH) and to the adsorption of methylene blue of the activated carbon. Activated carbon was prepared from fibers of empty fruit bunches of oil palm (fibers of EFB) pre-carbonized at 280 for 4 hours. Chemical activation was conducted to the sample for 25 hours with weight percentage of KOH of 25%, 50%, and…