Abstract : Single-crystal PbTiO3 layers were grown on (001) SrTiO3 substrates by molecular beam epitaxy using hydrogen peroxide as an oxidant. Phase composition and structural properties of the films were examined as a function of growth parameters. It was found that single-phase PbTiO3 films grew epitaxially at substrate temperatures of 600 degrees C and higher, whereas layers grown at lower temperature contained PbO inclusions. Growth of Pb(ZrTi)O3 (PZT) films by molecular beam epitaxy was demonstrated for the first time. Single-crystal, single-phase PZT films were grown on (001) SrTiO3 substrates at a growth temperature of 600 degrees C. In situ monitoring of the growth process by reflection high-energy electron diffraction revealed two dimensional growth mode for the end compounds of the PZT system, PbTiO3 and PbZrO3, and three-dimensional growth mode for PZT films of intermediate compositions.