In the title compound, (C(5)H(8)N(3))(2)[Co(H(2)O)(6)](SO(4))(2)·2H(2)O, the complete complex cation is generated by crystallographic inversion symmetry, such that the Co(II) cation is octa-hedrally coordinated by six water mol-ecules. The organic cation is essentially planar, with a maximum deviation of 0.013 (1) Å. In the crystal structure, the ions and mol-ecules are linked into a pseudo-layered three-dimensional supra-molecular network via O-H⋯O and N-H⋯O hydrogen bonds. Weak inter-molecular π-π inter-actions further stabilize the crystal structure [centroid-centroid distance = 3.5231 (4) Å].