Activated carbon can be produced from a large variety of raw materials, basically by two methods, physical and chemical activation or a combination of both. The adsorption properties of activated carbon vary with the feed materials used and the way of activation. Production cost may be lowered by choosing a cheap raw material and performing a suitable production process. Agricultural and forestry residues, or generally, biomass residue wastes could be used as suitable raw materials for the production of activated carbon. In the present work, different agricultural residues such as hard shells of apricot stones, almond, walnut and hazelnut shells, rice hulls and residues of liquorices were used as precursors. The activation was performed using phosphoric acid under the same conditions. The results showed that at the selected experimental conditions, the type of biomass as well as the final activation temperature, heating rate and impregnation rate of the chemical agent had the greatest influence on the quality of activated carbon. The quality of activated carbon was evaluated in terms of the iodine number reflecting the surface area. According to the results, activated carbon from the hard shells of apricot stones had the best adsorption properties and the largest surface area.