The crystal structure of trans-bis[(chloroacetato)-(α-picoline)]copper(II) has been determined by X-ray diffraction methods and refined by full-matrix least-squares procedures. The crystals are triclinic, space group P1, with a= 8·166, b= 9·231, c= 7·898 Å, α= 118° 25′, β= 107° 40′, γ= 100° 26′, and Z= 1. The molecule is strictly centrosymmetric and the copper atom is surrounded by four atoms in a square-planar environment with two Cu–N bonds, 1·989(6)Å, from the picoline ligands and two Cu–O bonds, 1·975(5)Å, from the chloroacetate groups. Two long ‘out-of-plane’ Cu ⋯ O distances, 2·707(7)Å, are formed from the remaining oxygen atoms of the chloroacetate groups. The angle between the ‘out-of-plane’ Cu ⋯ O direction and the normal to the square plane is 36·1°.