Novel highly porous carbon nanofiber (CNF)/cellulosic membranes were fabricated for water desalination using the forward osmosis (FO) process. Neat, carboxylic and amine functionalized CNFs were used for modification of cellulosic membranes. The prepared FO membranes were characterized by field emission scanning electron microscope (FESEM), atomic force microscope (AFM), hydrophilicity analysis and tensile strength. The hydrophilicity and porosity of modified cellulosic membranes were significantly enhanced. The membrane modified by amine functionalized CNFs exhibited the most promising results by showing high FO flux and low reverse solute flux. The osmotic water flux of the amine functionalized CNF membrane reached to 18 L/m(2) h when the feed and draw solutions were 10 mM and 1 M NaCl solutions, respectively. This result is above 2 times higher than FO water flux of the neat cellulosic membrane. The reverse salt flux of the amine functionalized CNF membrane was less than 0.5 g/m(2)h which is very low compared to the commercial cellulose triacetate (CTA) membrane. Surprisingly, the aforementioned membranes show a water flux of about 15 L/m(2) h under the FO mode when tested for seawater desalination. The structural parameter of membranes decreased significantly with the addition of functionalized CNFs in the casting, solution. Furthermore, the tensile strength measurement of the fabricated membranes with CNFs is also greater than that of the unmodified membrane. (C) 2015 Elsevier B.V. All rights reserved.