In enzymology, fumarate reductase (NADH) () is an enzyme that catalyzes the chemical reaction
The three substrates of this enzyme are fumaric acid, reduced nicotinamide adenine dinucleotide (NADH), and a proton. Its products are succinic acid and oxidised NAD<sup>+</sup>.
This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-CH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is succinate:NAD+ oxidoreductase. Other names in common use include NADH-fumarate reductase, NADH-dependent fumarate reductase, and fumarate reductase (NADH).