The grain growth of bicrystal has been studied using Monte Carlo (MC) simulation with the energetics of the system described by Potts' model. The influence of mobile and immobile impurities on the shrinkage rate of bicrystal in both 2D and 3D cases were analyzed. It was observed that the grain pinning effect increases with increase in percentage of impurities and it was stronger with mobile impurities compared to that of immobile impurities. The grain pinning also increases with size of impurity. The rate of grain shrinkage is relatively faster in 3D bicrystal than that of 2D bicrystal. It was shown that the maximum grain pinning is possible only up to certain percentage of impurities and beyond which it does not have any influence owing to the other factors such as size and strategic location of the impurities in the grain that dictates the grain boundary movements. (C) 2007 Elsevier B.V. All rights reserved.