The performances of stone and steel plate burr mills in the grinding of wheat were studied and the experimental results were compared. Plate clearance was found to be a significant factor in the variation in size distribution. In the case of stone plate burr mills, variation in milling speed caused a variation in product size at speeds up to 700 rpm, but variations were not significant at milling speeds between 700 and 1500 rpm. The fineness modulus exhibited a linear correlation with plate clearance for both stone plate and steel plate burr mills. The fineness modulus of the ground product from the stone plate mill was very small compared to that of the product from the steel plate burr mill. The results clearly indicated that the steel plate mill is suitable for coarser products while the stone plate mill is suitable for finer products. As the particle size of the ground wheat increased with the increasing plate clearance, the specific energy requirement decreased. The energy requirement of the steel plate mill was found to be significantly less than that of the stone plate mill, although of course the particle size of the product from the stone plate mill was comparatively larger.