||The work evaluates the effect of main process parameters, i.e. transmembrane pressure, TMP and cross-flow velocity, CFV on oil and protein rejection, ri and permeate flux, JVi using 22 experimental design. The ultrafiltration experiments were carried out using pilot installation with tubular ceramic 300 kDa membrane and model oil-in-water and BSA – water solutions. Ultrafiltration data obtained using experimental design technique was used to determine the regression coefficients of polynomial equations. These equations give information on non-conjugated as well as conjugated effects of two operating parameters on ultrafiltration process of model oil and BSA water solutions. Moreover, these equations helped to determine optimal conditions for ultrafiltration process from the point of view of membrane permeability and selectivity. Furthermore they can be useful while assessing the experimental conditions of ultrafiltration in real complex systems such as oily wastewaters produced by petroleum industry or marine transport and waste brines produced by fish industry.