In this study, the activated carbons were prepared from Oreganum stalks by chemical activation with phosphoric acide and zinc chloride. The influence of process variables such as impregnation ratio and impregnation time on the surface area of activated carbons was studied to optimize these parameters. The most important parameter was found to be the impregnation ratio. Under optimum conditions, for the activating agents phosphoric acid and zinc chloride, activated carbons with a surface area of 719 m(2) g(-1) and 944 m(2) g(-1) were obtained, respectively. Zinc chloride produced activated carbon with a higher micropore volume compared to that produced by phosphoric acid activation. The aqueous adsorption tests showed that the activated carbons had a notable adsorption capacity for both methylene blue and phenol. The adsorption capacity of activated carbon prepared with zinc chloride was more than that of activated carbon prepared using phosphoric acid. In addition, 73-86% of activating agent was recovered and reused in impregnation step.