Fac-bis(ethanolamine)orotatonickel(II), [Ni(HOr)(ea)(2)] and mer-bis(ethanolamine)orotatocopper(II) dihydrate, [Cu(HOr)(ea)(2)]. 2H(2)O were synthesized and characterized by elemental analysis, FT-IR, UV-Vis Spectroscopy and thermal analysis. In addition, their solid-state structures were determined by single crystal X-ray diffraction studies. Both the fiac-[Ni(HOr)(ea)(2)] (1) and mer[Cu(HOr)(ea)(2)](.)2H(2)O (2) complexes are isomorphous and crystallize in the triclinic space group P (1) over bar. The Ni2+ and Cu2+ ions are coordinated by two neutral ea ligands and one orotate dianion in a distorted octahedral fashion. The ea ligand acts as a bidentate donor through the amine N and hydroxyl O atoms, while orotate dianion is coordinated through deprotonated N3 pyrimidine atom and carboxylate oxygen atom as a bidentate ligand. Thermal decompositions of the complexes are studied in over the range 20-600 degrees C on heating in a static air atmosphere.