Microfiltration and ultrafiltration enable new opportunities of whey utilization in human nutrition. The implementation of these processes ensures appropriate microbiological quality and the preservation of the nutritional value of the product. The main disadvantage is the phenomenon of membrane fouling. The aim of this dissertation was to optimize the process of whey microfiltration in order to ensure aduequate micorbiological quality, to preserve the native whey proteins and to be tesetd as a pretreatment for enhancement of the ultrafiltration process. The filtrations were performed at different process temperatures (20ºC, 40ºC, 50ºC) by using ceramic membranes with different cut-offs (0,1 μm, 0,5 μm , 0,8 μm, 20 kDa). All samples of whey were analized for microbiological quality, physical and chemical properties. Microfiltration by ceramic membranes with mean pore diameter of 0,5 μm and 0,8 μm allowed preservation of the native wehy proteins. Microbial reduction rates decreased proportionally with the mean pore diameter of the used membranes. Regardless the process temperature, the membrane with mean pore diameter of 0,5 μm appeared to be optimal for purposes of preserving the nutritional value and achieveing proper micribiological quality of whey. According to all measured parameters, ultrafiltration process at 20ºC appeared to be the most appropriate for whey processing. Microfiltration of whey by ceramic membrane with the mean pore diameter of 0,8 μm didn´t significantly affect the efficiency of the ultrafiltration, regardless the process temperature. Microfiltration of whey by ceramic membranes with the mean pore diameter of 0,5 μm affected the efficiency of whey ultrafiltration by siginificantly increasing the permeate flux and reducing the fouling resistance. The described effects are more intensive at the process temperature of 20ºC.