Sugar, as the final product of the technology of sugar production, has to satisfy rigorous quality demands. Among others, it means low content of non-sucrose compounds, as well as the smallest possible. share of coloured matters. Ultrafiltration and nanofiltration can be one of the solutions for a more effective separation of non-sucrose compounds from the intermediate products from which sucrose can directly be crystallized. Applying this procedure energy can be saved and the environment protected. Syrup solution from sugar-beet processing which contains 39.2% d.m. is being ultra- and nanofiltered. Polymer membranes with different MWCO (15-20 kDa, 6-8 kDa and 0.5 kDa) are used. Effects of UF are carried at 30degreesC. and 60degreesC, with flow rates at 200 and 400 L/h and in the range of transmembrane pressure between 1-4 bar. NF is carried at 30degreesC and 50degreesC, with flow rates at 300 and 400 L/h and in the range of pressure between 1-30 bar. The separation of non-sucrose compounds is the most effective on a membrane with MWCO of 0.5 kDa, if the transmembrane pressure is kept at 30 bar and at a flow rate range between 300-400 L/h. Under these conditions colour and turbidity became lower for 76% and 80% respectively, if related to feed.