It belongs to the family of oxidoreductases, specifically those acting on NADH or NADPH with other acceptors.

The systematic name of this enzyme class is NADH:(quinone-acceptor) oxidoreductase.

Other names in common use include reduced nicotinamide adenine dinucleotide (quinone) dehydrogenase, NADH-quinone oxidoreductase, NADH ubiquinone oxidoreductase, DPNH-menadione reductase, D-diaphorase, and NADH2 dehydrogenase (quinone), and mitochondrial (mt) complex I.

NADH dehydrogenase is involved in the first step of the electron transport chain of oxidative phosphorylation (OXPHOS).

"[6] In the electron transport chain NADH is mainly used to create a concentration gradient of hydrogen in order to make ATP.