In the title hydroxamic acid derivative, C22H16Cl2N2O5, the nitro-substituted benzene ring forms dihedral angles of 26.95 (15) and 87.06 (15)°, with the 4-chloro- and 2-chloro-substituted benzene rings, respectively. The dihedral angle between the chloro-substituted benzene rings is 68.19 (13)°. The O atoms of the nitro group were refined as disordered over two sets of sites with equal occupancies. In the crystal, weak C-H⋯O(=C) hydrogen bonds link mol-ecules along [100].