The grain growth kinetics in the 0, 2, 4 wt.% CoO added ZnO-6 wt.% Bi2O3 system was studied using the simplified phenomenological grain growth kinetics equation G(n) = K.t.exp(-Q/RT) together with the physical properties of the sintered samples. The grain growth exponent value (n) and the apparent activation energy for the ZnO-6 wt.% Bi2O3 system was found to be 5.2 and similar to200 kJ/mol respectively. The addition of the CoO to the ZnO-6 wt.% Bi2O3 system had no effect in the grain growth. At 0% CoO addition the apparent activation energy was calculated as 204 kJ/mol and with 4 wt.% CoO addition it was calculated as 203 kJ/mol. (C) 2003 Elsevier Ltd and Techna S.r.l. All rights reserved.