In enzymology, a dimethylglycine dehydrogenase (EC 1.5.8.4) is an enzyme that catalyzes the chemical reaction

N,N-dimethylglycine + acceptor + H₂O sarcosine + formaldehyde + reduced acceptor

The 3 substrates of this enzyme are N,N-dimethylglycine, acceptor, and H₂O, whereas its 3 products are sarcosine, formaldehyde, and reduced acceptor.

This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-NH group of donors with other acceptors. The systematic name of this enzyme class is N,N-dimethylglycine:acceptor oxidoreductase (demethylating). Other names in common use include N,N-dimethylglycine oxidase, and N,N-dimethylglycine:(acceptor) oxidoreductase (demethylating). This enzyme participates in glycine, serine and threonine metabolism. It employs one cofactor, FAD.

• FRISELL WR, MACKENZIE CG (1962). "Separation and purification of sarcosine dehydrogenase and dimethylglycine dehydrogenase". J. Biol. Chem. 237: 94–8. doi:10.1016/S0021-9258(18)81367-9. PMID 13895406.
• HOSKINS DD, MACKENZIE CG (1961). "Solubilization and electron transfer flavoprtein requirement of mitochondrial sarcosine dehydrogenase and dimethylglycine dehydrogenase". J. Biol. Chem. 236: 177–83. doi:10.1016/S0021-9258(18)64450-3. PMID 13716069.