The monomeric title compound, aqua(nitrato-κ²O,O′)(nitrato-κO){4′-[4-(pyrimidin-5-yl)phenyl]-2,2′:6′,2″-terpyridine-κ³N,N′,N″}cadmium(II) dihydrate, [Cd(NO₃)₂(C₂₅H₁₇N₅)(H₂O)]·2H₂O, consists of a seven-coordinated Cd^II centre bound to the novel 4′-[4-(pyrimidin-5-yl)phenyl]-2,2′:6′,2″-terpyridine (L1) ligand (behaving as a tridentate chelate), two nitrate anions (as chelating-bidentate and monodentate ligands) and a water O atom. Both chelating groups define the base of a slightly deformed pentagonal bipyramid, while the monocoordinated ligands occupy the apices. The four heterocycles in L1 form a planar skeleton, while the central benzene ring is rotated from this planar geometry by more than 30°, probably because of packing effects. Noncovalent interactions lead to the formation of columnar arrays parallel to [100].