In the title compound, (C(3)H(5)N(2))[Co(C(4)H(5)NO(4))(2)], the cation and anion are located on a twofold rotation axis and inversion center, respectively. Inter-molecular N-H⋯O hydrogen bonds link the cations and anions into layers parallel to the ab plane. The crystal packing also exhibits weak C-H⋯O hydrogen bonds, including bifurcated hydrogen bonds, and C=O⋯π inter-actions.