Cupriavidus necator (previously Ralstonia eutropha) is a highly flexible chemolithoautotrophic bacterium capable of oxidizing molecular hydrogen to serve as the sole electron source and assimilate inorganic carbon. Furthermore, this aerobic Knallgas microorganism can also rely on carbon sources to drive its metabolism in a heterotrophic fashion. This metabolic flexibility makes C. necator a potentially invaluable tool for a plethora of applications including the production of chemicals and bioplastic precursors as well as hydrogen-driven cofactor regeneration and biocatalysis. In this chapter, the complex metabolism of C. necator and key players of autotrophic growth (hydrogenases) are introduced and summarized. Furthermore, state-of-the-art cultivation techniques and methodologies for the biotechnological utilization of C. necator are highlighted.