Epitaxial thin ferroelectric films of Pb(Zr0.53Ti0.47) (PZT) were successfully grown on Sr(Nb)TiO3 (SNTO) single crystal substrates by high-pressure rf sputtering. Pure O2 was used as working gas at a pressure above 1 Torr. Deposition temperature was varied from 550°C to 600°C. Under these conditions we were able to deposit films at a rate of 2.7 Å/min. Their crystalline properties, evaluated by Θ/2Θ, ω and φ scans, showed both in-plane and out of plane orientation. Film composition and film-substrate interface characteristics were studied by Rutherford Backscattering Spectroscopy (RBS). For RBS data the composition ratios for the films were calculated having obtained the expected values for a stoichiometric composition. A very thin diffusion layer of Pb at the film-substrate interface was also introduced. However, the deficiency in Pb, which is correlated to the presence of oxygen vacancies, is lower in our films produced at high O2 pressure than those reported for films produced by sputtering at lower pressures. The ferroelectric hysteresis loops measured in the Pt/PZT/SNTO heterostructures show good ferroelectric behavior with remanent polarizations of 12μ Ccm-2 and coercive field of 50kVcm-1 at 5V. The high-pressured technique representing a useful and capable method capable of obtaining in situ epitaxial, fully oxygenated, pyrochlore-free ferroelectric thin film with high quality structural, compositional and dielectric properties, without post deposit treatment.