The application of variable energy positron annihilation spectroscopy (VE-PAS) methods to the study of perovskite oxide, ABO3, material thin films and near-surface regions is reviewed. The primary focus is on ferroic perovskite titanate oxide materials SrTiO3 and Pb(ZrxTi1-x)O3, but studies of BaTiO3, LaxSr1-xCoO3, La0.67Sr0.33MnO3 and YBa2CuO7-d are also included. Characterization of single layer and multilayer structures is discussed. The methods, in particular positron annihilation lifetime spectroscopy, allow the identification of cation vacancy defects at both the A- and B-sites with parts per million sensitivity. Varying oxygen deficiency is often observed to result in marked changes in PAS spectra; these effects are reviewed and discussed.