Filtration studies on the performance of titanium dioxide membranes fused on porous ceramic tubes with pore diameter of 0.2 microns ate reported. Solutions of sodium nitrate in deionized and tap water were studied to determine the fouling characteristics. The membranes were cleaned frequently to evaluate the efficiency of the cleaning process and to establish the degree to which the membrane returned to their original filtering condition. Selected solutions containing Direct Red 2 (C.I. #23500, MW = 724), an anionic direct dye, were also studied to evaluate the filtering characteristics of ions with larger molecular weight. Tubes were supplied by Rhone-Poulenc Tech-Sep, Shelton, CT. Results show that the charge or ionic nature of the membrane surface was responsible for the ion rejections and decreased as the salt concentration was raised from 50 to 5,000 ppm. The results are interpreted in terms of past research involving inorganic microfilters.