Pb(Zn 1/3 Nb 2/3 )O 3 (PZN) thin films were grown by metalorganic chemical vapor deposition (MOCVD). We systematically investigated what effects the supply sequence of source gases used in MOCVD and substrate types and orientations had on the constituent phase. Alternate-MOCVD, in which source materials of the A-site (Pb) and B-site (Zn and Nb) are alternately supplied to create the perovskite structure ABO 3 , which efficiently increases the phase purity of the perovskite phase in the PZN-pyrochlore phase mixture. A relatively smaller mismatch between the PZN and the substrate than that between the pyrochlore phase and the substrate also increased the phase purity of the PZN. As a result, single-phase PZN films were successfully grown on (110) and (111)MgO substrates by alternate-MOCVD.