© 2020 Desalination Publications. All rights reserved.The efficacy of nanofiltration (NF) in removing sulfate from a high sulfate content (370–460 mg/L) surface water was investigated. NF tests were carried out using a laboratory-scale cross-flow NF module operated in total-recycle (full-recycle) mode. Membranes of varying characteristics; namely, DK-NF (Desal DK: GE Osmonics, USA), DL-NF (Desal DL: GE Osmonics, USA), and NF270 (Dow Filmtec Co., USA) were tested, and the effects of main operational parameters of cross-flow veloc-ity, trans-membrane pressure, and pretreatment on permeate flux and sulfate removal were evalu-ated. The NF270 membrane exhibited the highest permeate flux and was found to be the best of the three membranes tested, with over 98% sulfate removal. The DK-NF membrane, which was poor in performance with a high flux decline, provided the lowest sulfate removal, lowest permeate flux, and highest fouling. Microfiltration (2.5-µm), as pretreatment, provided no considerable improvement in permeate flux. When the effects of operational parameters on NF performance using the DL-NF membrane were sought, it appeared that permeate flux, and sulfate removal efficiency did not change at all with trans-membrane pressure and cross-flow velocity. The study is expected to provide useful information about the NF of drinking water with high sulfate content in the future.