Transparent films of CaTiO3:Pr3+ were deposited by radio frequency sputtering and annealed in air at temperatures ranging from 700 to 1000 degrees C. The chemical, structural and optical characteristics of the films were evaluated. The films of typically 200 nm thick consist of grains in the nanometer scale with sizes controlled by thermal treatment. They show the typical red emission of PP ions in CaTiO3 when excited either in the fundamental band of the titanate host or in the emitting D-1(2) Manifold. Comparing with the properties of the micron-sized powder ceramic used as the target, a shortening of the fluorescence decay profile and a blue shift of the excitation spectrum are evidenced, which account for particle size effects. (c) 2006 Elsevier B.V. All rights reserved.