In enzymology, an urethanase () is an enzyme that catalyzes the chemical reaction
Thus, the two substrates of this enzyme are urethane and H<sub>2</sub>O, whereas its 3 products are ethanol, CO<sub>2</sub>, and NH<sub>3</sub>.
This enzyme belongs to the family of hydrolases, those acting on carbon-nitrogen bonds other than peptide bonds, specifically in linear amides. The systematic name of this enzyme class is urethane amidohydrolase (decarboxylating). This enzyme is also called urethane hydrolase.