The Co atom in the title cobaloxime, [CoCl(C14H11N2O2)(2)(C12H27P)], is octahedrally coordinated to the two bidentate diphenylglyoximato ligands, approximating a plane with the Cl and P atoms located above and below the plane. The diphenylglyoximato moieties are themselves bent 6.6(1) and 9.8(1)degrees from the central plane of the four N atoms by the bulk of the trin-butylphosphine ligand. The four phenyl rings of the two diphenylglyoximato groups form a propeller geometry with an average rotation from the central plane of 47 (5)degrees.