The fine grinding characteristics of hard materials such as synthetic diamond and alumina were investigated by means of an attrition mill. The grinding kinetics approach was successfully applied to the analysis of product size distributions obtained under various process conditions. As a result, the higher grinding rate of hard materials was proven to be obtained with the larger media size, the higher impeller rotational velocity and the larger amount of the feed within the studied range. It was also found that the volume of the dispersing liquid has an optimal value for the grinding of alumina.