This study was contained on the comparative leaching behavior of old and fresh copper flotation tailings for Sarcheshmeh copper mine. The old tailings from this operation accumulated in the tailing dam, while the fresh material is produced at the rate of 40,000 tons solid/day. The old tailings considered for the present study assayed 0.22% total copper, while the fresh material contained 0.18% total copper, that the one-third of them be oxidized. This study involved three stages. shake flask experiments, performing bioleaching process in tank and finally column bioleaching. In this investigation after finding optimum factors for each parameter in shake flask experiments on two species of tailings, we applied this condition for other kinds of experiments.The results of shake flask tests showed, in the non inoculated leaching experiments, fresh and tailing dam material yielded, respectively, 48 and 49 percent recovery in 19 days while externally inoculated cultures achieved 72 and 60 percent copper extraction in the same leaching time. After 7 days of operation the best results indicated 64 and 68 percent total copper extraction in tank tests for old and fresh tailings respectively. Before using columns for bioleaching process, the materials were agglomerated and the best result achieved with 175 gr/lit concentrations of sulfuric acid and water.The result of final tests in columns showed, without any inoculation with tailings fresh and old yielded, respectively, 47 and 39 percent copper recovery in 80 days, while with inoculation bacteria in columns achieved 72 and 62 percent copper extraction in the same leaching time.