Retention of a wide variety of organic pollutants including endocrine disrupting chemicals, plastic additives and low molecular weight priority pollutants from aqueous solutions by the use of many recent type nanofiltration (NF)/reverse osmosis (RO) membranes was investigated. Retention was dependent on membrane type and solute size though other factors such as solute-membrane interaction influenced the result. At low pressure of 0.3 MPa, the high desalting membranes effectively retained virtually all of the semi-volatile organic compounds (SVOCs) at greater than 90% but not the volatile organic compounds (VOCs). The low desalting membrane UTC60, rejected most of the VOCs at lower than 20%. The molecular weight of solutes was useful but the molecular width was a more appropriate parameter for describing the sieving retention by membranes. A multi-linear regression analysis gave the best fitting when the retention was correlated with molecular width, molecular length and logarithm of octonol-water partition coefficient of the target solutes. The prediction indicated that a higher retention will be obtained for a more hydrophobic molecule with a larger width and length. (C) 2003 Elsevier B.V. All rights reserved.