Membrane separation is a process in which the membrane separates the inlet stream on retentate (part of the inlet stream retained on the membrane) and the permeate (part of the inlet stream that passed through the membrane). Separation is based on the ability of the membrane to transport one component from the inlet stream more easily than other components based on the physical and chemical properties of the membrane and the permeating component. In this thesis a membrane ultrafiltration separation of fatty acid ethyl esters from mixture of ethanol, sunflower oil and glycerol, was conducted. Three types of polymer membranes were used: PT membrane produced by polyethersulfone with a molecular weight cut-off (MWCO) of 5000 Da and two polyamide membranes, GK with a MWCO of 3000 Da and GH with a MWCO of 2000 Da. Fatty acid ethyl ester (biodiesel) were produced by transesterification and the goal was to isolate them directly from the mixture after the reaction. The most efficient membrane for glycerol removal is PT membrane working at 6 bar (6×105 Pa). It reduced the concentration of glycerol by 38,3 % and ethanol by 32,5 % compared to starting mixture. The most efficient membrane for reducing the concentration of ethanol from the starting mixture is GK membrane under the same conditions (6 bar) and reduction of 57,8 % of ethanol and 8,2 % of glycerol, compared to concentration in starting mixture, was achieved.