The structure of dichlorobis-(4-ethylpyridine)copper(II) has been determined from three-dimensional single-crystal X-ray data collected by standard film techniques and refined by least-squares methods to R= 0·105 for 1130 observed reflections. The crystals are monoclinic, space group P21/c, a= 11·36, b= 4·00, c= 17·58 Å, β= 112·8°, with Z= 2. The molecule is centrosymmetric; Cu–Cl 2·28 and Cu–N 2·00 Å. The ethyl groups are very loosely packed in a manner quite different from the vinyl groups in the related dichlorobis-(4-vinylpyridine)-copper(II).