This paper presents a study of the influence of particle size on the structural and dielectric properties of Pb 0.85 La 0.15 TiO 3 (PLT15) ferroelectric ceramic samples. The samples were prepared with average grain size of 1.69±0.08μm and 146±8nm using, respectively, conventional and spark plasma sintering techniques. A decrease in the tetragonality degree as the crystallite size decreased was explained by an internal stress caused by the existence of a large amount of grain boundaries. The local structure exhibited no significant modification and the dielectric measurements showed a diffuse phase transition and a reduction in the permittivity magnitude at T m as the average grain size decreased. The nanostructured ceramic sample prepared at a relatively lower temperature and sintering time presented a dielectric constant value of approximately 2000 at room temperature.