In the title complex, [Cu(C2H8N2)(2)(H2O)(2)](C13H9O2)(2)center dot 2.66H(2)O,the Cu-II centre (located at an inversion centre) is coordinated by two bidentate ethylenediamine (en) ligands and two water O atoms in a typical Jahn-Teller distorted octahedral geometry. The amino groups and the water molecules are disordered over two distinct crystallographic positions with occupancies of 1/3 and 2/3. In the crystal, the cations and anions are disposed in alternating layers. One of the water molecules of crystallization is disordered and the other has a fractional occupation. In the 2/3 occupancy component, water molecules are organized into a chain composed of hexameric units interconnected by carboxylate bridges.