In the title complex, mer-diaqua[2,6-dioxo-1,2,3,6-tetrahydropyrimidine-4-carboxylato(2-)]bis(1H-imidazole-kappaN(3))cobalt(II), [Co(C(5)H(2)N(2)O(4))(C(3)H(4)N(2))(2)(H(2)O)(2)], the Co(II) ion is coordinated by a deprotonated N atom and the carboxylate O atom of the orotate ligand, two imidazole N atoms and two aqua ligands in a distorted octahedral geometry. The title complex exists as discrete doubly hydrogen-bonded dimers, and a three-dimensional network of O-H...O and N-H...O hydrogen bonds and weak pi-pi interactions is responsible for crystal stabilization.