During microfiltration, limiting (J(L)) and critical flux (J(C)) are essential. Using these concepts, the operational zones, have been established for flux (J) versus transmembrane pressure (Delta P-T). However, the resistance model cannot be used for an accurate description of these operational zones. The aim of this work was to evaluate the application of an equation for process parameters determination during skim milk microfiltration. The exponential model, J = J(L)(1 exp(-Delta P-T/(Delta P-T)(C)), allowed a direct determination of J(L) and the critical Delta P-T ((Delta P-T)(C)) and allowed the calculation of J(C) and the limiting Delta P-T ((Delta P-T)(L)). The effect of temperature, concentration factor, and cross-flow velocity over J(L) and (Delta P-T)(C) were evaluated. For J(L) and (Delta P-T)(C), a good fitting was obtained (Radj(2) = 98.12%; R-adj(2) = 97.83%, respectively). These results allow to predict the limiting and critical points for given values of the concentration factor, cross-flow velocity and temperature. Moreover, determination of the operational zones could be established.