The aging properties of 0.01 mol% Mn-doped Ba0.8Sr0.2TiO3 ceramics have been investigated from 30 degrees C to 400 degrees C at various frequencies. Decreases in epsilon'(T) of the aged sample compared to the fresh one around the tetragonal-cubic transition and in the regime of diffusion have been observed. The activation energy E-a = 1.25 eV obtained from the J-T loop at zero electric field indicates that oxygen vacancies dominate in the aging. The symmetry-conforming principle of point defects was employed to explain the time and temperature dependence of aging in the dielectric constant and double/constricted P-E loops of the samples aged in the paraelectric and ferroelectric state. (C) 2009 Elsevier B.V. All rights reserved.