Palm oil and oleic acid are found in many solutions from a variety of production processes such as transesterification and hydrolysis. Feasibility study on ultrafiltration of glycerin solution containing palm oil and oleic acid is limited. In this work, the effects of different palm oil concentrations, different oleic acid concentrations, blend of different palm oil and oleic acid concentrations, and pH on membrane flux decline and rejection ability were examined. The present studies showed that only palm oil was contained in the glycerin solution where the palm oil molecule tended to condense on the membrane surface. The oleic acid molecule in oleic acid-glycerin solution tended to foul into the membrane interpore. The blend of palm oil and oleic acid in glycerin solution performed better in flux decline than the solution containing either palm oil or oleic acid alone. However, the pH adjustment of original solution would cause the degradation of membrane performance in terms of final permeate flux and flux decline percentage. This study demonstrated that ultrafiltration was capable of removing palm oil, oleic acid and blend of palm oil and oleic acid from glycerin solution, up to 87.00%, 98.59% and 95.60%, respectively. (C) 2011 Elsevier B.V. All rights reserved.