In enzymology, a deoxycytidine deaminase () is an enzyme that catalyzes the chemical reaction
Thus, the two substrates of this enzyme are deoxycytidine and H<sub>2</sub>O, whereas its two products are deoxyuridine 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 cyclic amidines. The systematic name of this enzyme class is cytidine/2'-deoxycytidine aminohydrolase. This enzyme participates in pyrimidine metabolism. As every deoxycytidine deaminase is also a cytidine deaminase, they share the same EC number. The recommended name assigned by the IUBMB is cytidine deaminase.