Epitaxial MgO films were grown on Si(1 1 1) substrates at 800 degrees C using methylmagnesium tert-butoxide ((MeMgOBu)-Bu-t) as a single precursor under high-vacuum conditions (5 x 10(-6) Torr). The crystalline structure, morphology, and chemical composition of the deposited films were investigated by X-ray diffraction, X-ray pole figure analysis, scanning electron microscopy, and X-ray photoelectron spectroscopy. The results show that epitaxial MgO films with correct stoichiometry can be deposited on Si(1 1 1) at 800 degrees C. The single precursor methylmagnesium tert-butoxide has been found suitable for the epitaxial growth of MgO on Si(1 1 1) substrates.