In this work, the dielectric properties of La0.8Bi0.2Fe0.7Mn0.3O3 ceramics have been investigated in a temperature range of 76-320 K and a frequency range of 300 Hz-10 MHz. Two thermally activated dielectric relaxations were observed with the activation energy around 0.283 +/- 0.007 eV for the low-temperature relaxation and 0.268 +/- 0.007 eV for the high-temperature relaxation. Annealing in N-2 and O-2 can destroy and create the high-temperature relaxation, respectively. But the treatments have no significant influence on the low-temperature relaxation. The low-temperature relaxation was found to be bulk effect related to the dipolar effect due to the hopping polarons, and the high-temperature relaxation was associated with the Maxwell-Wagner relaxation due to surface-layer effect caused by hopping polarons blocked and trapped at the surfaces of the sample. (C) 2012 Elsevier B.V. All rights reserved.