A computer model and simulation program were elaborated for studying the stationary state processes of grinding mills. The computer model was developed on the basis of the axial dispersion model taking into consideration also the effects of mixing of the ground material. The final form of the model was expressed as a set of recursive equations, the successive solution of which converges to the stationary state of the mill. By means of the newly developed simulation program, the effects of parameters of a continuous grinding mill on the size distribution of the particulate product were studied for selection and breakage distribution functions of the form S(L)=KsLalpha and B(L,l)=(L/l)(beta), respectively. The program, however, can be utilized in the simulation-based analysis and design of both continuous and batch grinding devices by selecting the respective input-output as well as the mixing conditions of the computer model.