In enzymology, an UDP-sugar diphosphatase () is an enzyme that catalyzes the chemical reaction
Thus, the two substrates of this enzyme are UDP-sugar and H<sub>2</sub>O, whereas its two products are UMP and alpha-D-aldose 1-phosphate.
This enzyme belongs to the family of hydrolases, specifically those acting on acid anhydrides in phosphorus-containing anhydrides. The systematic name of this enzyme class is UDP-sugar sugarphosphohydrolase. Other names in common use include nucleosidediphosphate-sugar pyrophosphatase, nucleosidediphosphate-sugar diphosphatase, UDP-sugar hydrolase, and UDP-sugar pyrophosphatase.
As of late 2007, 6 structures have been solved for this class of enzymes, with PDB accession codes , , , , , and .