250 nm-thick PZT films were grown on (001)lr/(001)MgO substrates by metalorganic chemical vapor deposition (MOCVD). It was ascertained that PZT films on lr substrates are epitaxially grown without the formation of large amount of lrO 2 phase. Crystal structure and the electrical properties of Pt/PZT/(001)lr/(001)MgO structure was compared with Pt/PZT/ (001)c SrRuO 3 /(001)SrTiO 3 structure with the same Zr/(Zr+Ti) ratio of 0.50. X-ray diffraction pattern was almost the same to be identified as (001)- and (100)-oriented tetragonal PZT phase. P-E hysteresis loops and saturation properties of the remanent polarization ( P r ) and the coercive field ( E c ) were also the same, because of the same volume fraction of (001)-oriented grains that contributed to polarization. On the other hand, the leakage current density of Pt/PZT/lr/MgO structure was superior to that of Pt/PZT/SrRuO 3 /SrTiO 3 structure. As a result, lr/MgO substrate is suitable for epitaxial PZT film with low-leakage and good ferroelectricity.