The crystal structure of the title complex, trans-dichloridotetrakis[1-phenyl-3-(1 H-1,2,4-triazol-1-yl-κ N4)propan-1-one]copper(II) hexahydrate, [CuCl2(C11H11N3O)4]·6H2O, is isomorphous with that of the corresponding nickel and cobalt compounds. The complex has crystallographic inversion symmetry with the CuII atom on an inversion centre. Each CuII atom is six-coordinated by one N atom from each of the four 1-phenyl-3-(1 H-1,2,4-triazol-1-yl)propan-1-one ligands in the equatorial plane and by two chloride ligands in axial positions. The structure includes a centrosymmetric irregular up-up-down-down (uudd) water tetramer cluster and O-H...Cl hydrogen bonds. Intermolecular C-H...Cl hydrogen bonds exist between adjacent molecules, resulting in a three-dimensional supramolecular network. [ABSTRACT FROM AUTHOR]