Crystals of the title compound are monoclinic, a= 4·465(1), b= 10·262(2), c= 17·567(5)Å, β= 95·44(2)°, Z= 4, space group P2₁/n. The structure was determined from X-ray diffractometer data by Patterson and Fourier syntheses, and refined by full-matrix least-squares calculations to R 0·046 for 1656 observed reflections. The cadmium is co-ordinated to one nitrogen and five oxygen atoms in distorted octahedral geometry. Each of the two independent cyanoacetate ligands co-ordinates to three symmetry-related cadmium atoms to give a three-dimensional polymeric lattice. One ligand co-ordinates through two oxygen atoms, one of which is also bridging, while the other co-ordinates through two oxygen atoms and the nitrogen atom. In common with many other acetates, the metal atom is not chelated, the ligands acting as bridging molecules.