Mine water, specifically from gold and coal mines in South Africa, contains large quantities (up to 3 g/l = 3000 ppm) of sulphate and can be very acidic (pH 2-4). A study was done to investigate the performance of commercially available nanofiltration (NF) membranes for the removal of sulphates and other ions at acidic conditions. The NF measurements were carried out in a dead-end membrane set-up at pressures between 3 and 20 bars. At neutral pH, membranes were identified with a sulphate rejection of 95-99% and a water flux of 2-7 l/m(2).h.bar. At lower pH values, the performance decreases due to the presence of a higher fraction of monovalent HSO4- ions and as well as a possible change in the membrane charge from negative to positive. However, there are still some membranes (from Filmtec) which are suitable for mine water with a pH of 4 and a salt loading of 2500 ppm. The water flux of these membranes is, however, below 4 l/m(2).h.bar. Surprisingly multi-charged ions like Ca2+ and SO42- as well as single-charged ions like Na+ and Cl- are rejected with values larger than 90%.