In the title complex, [CuCl(C(16)H(16)N(2)O(2))(2)]ClO(4), the Cu(II) ion is coordinated by four N atoms from two chelating 2,9-dieth-oxy-1,10-phenanthroline ligands and one chloride ion in a slightly disorted trigonal-bipyramidal environment. Two N atoms and the Cl atom are in equatorial positions while the remaining two N atoms occupy apical sites, the equatorial Cu-N bonds being significantly longer than the two apical Cu-N bonds. The N=C-O-C torsion angles involving the four eth-oxy groups are in the range 161.5 (8) to 177.0 (5)°. In the crystal structure, there are significant π-π stacking inter-actions between inversion-related rings of phenanthroline groups with centroid-centroid distances in the range 3.649 (4)-3.790 (4) Å.