In this study, adsorption of the methylene blue dye was investigated by using apricot stones, applied chemical and microwave modification. Adsorption is suitable for pseudo-second-order kinetic model and chemisorption was determined as rate controlling step. It was determined that the pore diffusion is not sole rate-limiting step and other mechanisms also play a role on the adsorption. A significant increase was observed in the adsorption capacity as the pH value increased. Adsorption was best described with Langmuir isotherm. As the temperature increased, adsorption capacity showed an increase, which revealed endothermic nature of the adsorption.