In enzymology, 2'-hydroxydaidzein reductase () is an enzyme that catalyzes the chemical reaction
The three substrates of this enzyme are 2'-hydroxydaidzein, reduced nicotinamide adenine dinucleotide phosphate (NADPH), and a proton. Its products are 2'-hydroxy-2,3-dihydrodaidzein and oxidised NADP<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 2'-hydroxy-2,3-dihydrodaidzein:NADP+ 2'-oxidoreductase. Other names in common use include NADPH:2'-hydroxydaidzein oxidoreductase, HDR, and 2'-hydroxydihydrodaidzein:NADP+ 2'-oxidoreductase. This enzyme participates in isoflavonoid biosynthesis.