The title compound, [Co(C(18)H(18)N(2)O(4))Cl(H(2)O)]·H(2)O, contains a distorted octa-hedral cobalt(III) complex with a 6,6'-dimeth-oxy-2,2'-[ethane-1,2-diylbis(nitrilo-dimethyl-idyne)]diphenolate ligand, a chloride and an aqua ligand, and also a disordered water solvent mol-ecule (half-occupancy). The Co(III) ion is coordinated in an N(2)O(3)Cl manner. Weak O-H⋯O hydrogen bonds may help to stabilize the crystal packing.