This chapter reviews the technology of bioleaching. Bioleaching technology has a vast potential to make the environment safer and greener and can serve as a promising alternative to traditional mining techniques which contribute to environmental pollution. Microbial leaching/bio leaching is a clean technology that offers an economic substitute for the mining industry at low cost and less capital inputs requirements as compared to conventional methods. Very rich microbial diversity is found in the bioleaching environment which includes bacteria, fungi, algae and some of the yeasts. Bioleaching generally implies using microorganisms to convert solid metal values into their water soluble forms. The mining industry has major applications of commercial scale bioleaching. The process of bio-mining involves an economical metal recovery in large scale operations of mining industries using applications of microbial metal mobilization processes. When conventional methods prove uneconomical for metal recovery from mining and other industrial waste products, then microbial leaching processes find greater use and applicability.