In the title compound, [Co(C(5)H(9)O(2))(2)(C(12)H(8)N(2))(H(2)O)], the Co(II) atom is coordinated in a distorted octahedral environment by three carboxyl O atoms of two trimethyl-acetate ligands, one aqua O atom and two N atoms from 1,10-phen-anthroline. The crystal structure is stabilized by O-H⋯O hydrogen bonds and π-π stacking inter-actions [inter-planar distance between inter-digitating 1,10-phenanthroline ligands = 3.378 (2) Å].