Activated carbon is widely used in various processes as an inexpensive and effective adsorbent. The adsorption properties of activated carbon vary with the feed materials used and the method of activation. The use of an inexpensive material and performing a suitable, production method may help to generate a low cost product. Agricultural wastes could be considered as suitable raw materials for the production of activated carbon. In this work, activated carbon was produced by chemical activation with phosphoric acid of agricultural wastes such as bagasse, hard shells of apricot stones, almond, walnut and hazelnut shells. The effects of various preparation variables on both yield and quality of the prepared carbon were studied. The results showed that the selection of final activation temperature, heating rate, activation time and impregnation rate of the chemical agent was important in determining the quality of activated carbon obtained. The surface area and ash content of the activated carbon produced were compared to those of imported commercial samples. According to the results obtained, activated carbon from the hard shells of apricot stones have the best adsorption properties and the highest surface area. This activated carbon could be used in the separation of metal ions from wastewaters.