Transition metals are essential constituents of all living organisms, playing crucial structural and catalytic parts in many enzymes and transcription factors. However, transition metals can also be toxic when present in excess. Their uptake and efflux rates must therefore be carefully controlled by biological systems. In this chapter, we summarize the current knowledge about uptake and efflux systems in Mycobacterium tuberculosis for mainly three of these metals, namely iron, zinc, and copper. We also propose questions for future research in the field of metallobiology of host-pathogen interactions in tuberculosis.