In the title coordination polymer, [Cd₂(C₄H₄O₄)(NO₃)₂(C₁₂H₈N₂)₂(H₂O)₂](n), the Cd(II) ion is seven-coordinated within a distorted penta-gonal-bipyramidal O₅N₂ environment. The succinate anions, located on an inversion centre, adopt a bis-monodentate bridging mode, leading to the formation of rods along [100]. The rods are connected by O-H⋯O hydrogen bonds between the coordinating water mol-ecules and nitrate O atoms of adjacent rods; the same type of hydrogen bonds are also observed between water and carboxyl-ate O atoms within the rods. π-π stacking inter-actions with a minimum plane-to-plane separation of 3.462 (2) Å occur between phenanthroline ligands.