Bioleaching is the technique of using microorganisms to release valuable metals in low concentrations from solid materials. The process depends on a number of parameters, such as acid pH, temperature and oxygen content. It involves two mechanisms, direct and indirect.Furthermore, this practice could be implemented in various types of bacterial leaching systems, including heap bioleaching, tank bioleaching and in situ bioleaching. The success of microorganisms in mobilizing metals from ores is consistent with their possession of an arsenal of genes encoding enzymes involved in bioleaching function. Ultimately, as richer ores are depleted by growing global demand, the importance of bioleaching is likely to increase in the future, as low-metal ore deposits are exploited in an economically beneficial and less environmentally polluting way.