The present study reports post-electrospinning crosslinking of guar/polyvinyl alcohol/citric acid nanofiber membranes by heat treatment. Porous, interconnected non-woven nanofiber membranes (average diameter 194 +/- 23 nm) were electrospun from a homogeneous blend of 1 wt. % guar gum and 8 wt. % polyvinyl alcohol solution (3 :7 weight ratio) containing 5 wt. % (by the total weight of the solution) citric acid. The electrospun nanofiber membranes were then cured at 140 degrees C for 2 hours. The crosslinked nanofiber membranes were insoluble in water, while the non-crosslinked membranes dissolved instantaneously. The Fourier transform infrared spectrum investigates that crosslinking of guar/polyvinyl alcohol occurred through esterification reaction during heat treatment.