Submicron thick ferroelectric AgTa0.38Nb0.62O3 (ATN) films have been prepared by pulsed laser deposition technique onto Pt80Ir20 polycrystalline and La0.7Sr0.3CoO3/LaAlO3 single crystal substrates. ATN/Pt80Ir20 films have been found to be (001) preferentially oriented, while the epitaxial quality of ATN/La0.7Sr0.3CoO3/LaAlO3 heterostructures has been ascertained. Comparative analysis of the temperature and frequency dependencies of the dielectric permittivity ε′ and loss tan δ in ATN films and bulk ceramics shows that in films: the coupled structural-ferroelectric monoclinic M1-to-monoclinic M2 phase transition occurs at the temperature 60° lower than in ceramics, thus the temperature stability of ε′ and tan δ in films is improved and occurs in extended temperature range. Reliable tracing of the ferroelectric hysteresis polarization versus electric loops indicates the ferroelectric state in ATN films at temperatures below 125 K and yields the remnant polarization of 0.4 μC/cm2 @77 K. Weak frequency dispersion, high temperature stability of the dielectric properties, as well as low processing temperature of 550 °C, are the most attractive features of ATN films. © 2000 American Institute of Physics.