Highly oriented perovskite films of PbMg1/3Nb2/3–PbTiO3 and PbSc1/2Nb1/2O3–PbTiO3 with compositions near the morphotropic phase boundary were formed by pulsed laser deposition on La0.5Sr0.5CoO3/MgO (100). The dielectric properties of the films were studied over the frequency range of 100 Hz–1 MHz in the temperature range 20–350 °C. The room temperature polarization and dielectric permittivity of 250-nm-thick films were close to those in bulk ceramics. The films exhibited relaxor-type behavior with thermal hysteresis and with the temperatures of the dielectric peaks corresponding to those in the bulk. The width of the transition in the films was larger than in bulk ceramics. The properties of the films were found to be influenced by the small grain size rather than by the interfaces of the films. © 1999 American Institute of Physics.