In the structure of the title complex, [Cu(C2O4)(C10H9N3)-(H2O)]center dot H2O, the Cu-II atom displays a square-pyramidal geometry, being coordinated by two N atoms from the di-2-pyridylamine ligand, two O atoms from the oxalate group and one O atom of a water molecule. The complex molecules are linked to form a three-dimensional supramolecular array by hydrogen-bonding interactions between coordinated/uncoordinated water molecules and the uncoordinated oxalate O atoms of neighboring molecules.