Peripheral grinding is inherently complex due to peculiar factors such as: the non deterministic microgeometry of the grinding wheel, the composition of the grinding wheel, essentially non homogeneous, the cutting process dynamics, where the grains’ cutting edges operate on a surface whose microgeometry is the result of the cutting actions of the preceding abrasive grains.This paper compares the results of the experimental analysis of the effect of single cutting grains on the actual microgeometry of worked surfaces, and the results obtained by a FEM cutting model where the measured microgeometry of the cutting grains is considered.