Highly porous nanofibrous membranes with high permeability, low weight and small pore size are widely employed for various filtration applications. The nanofibrous membranes showed superior advantages such as higher flow rate compared to commercially available membranes with the same pore size. Although nanofibrous membranes with increased permeability were successfully utilized for microfiltration, their application for ultra/nanofiltration is still challenging due to the typical achieved pore size. Thin film composites (TFCs) are a group of developed membranes for ultra/nanofiltration. TFCs consist of a selective thin layer (typically fabricated by (surface polymerization) on top of a non-homogenous porous substrate (commonly produced via interfacial polymerization). In this study, nylon 6 nanofibrous membrane with high porosity and permeability was employed as the substrate for fabrication of TFC. The effect of the solution concentration as well as electrospinning time on the performance of the electrospun nanofibrous membrane was investigated. The results showed that by increasing the concentration of the polymer solution, the diameter of the nanofibers was increased due to increased viscosity of the solution, while the air permeability was reduced as a result of bigger diameter of the nanofibers and smaller pores size. Moreover, the air permeability was lower at shorter electrospinning time due to the lowered thickness of the membrane and pores length. The active thin layer was fabricated by electrospraying of poly vinylalcohol (PVA) on the surface of porous nanofibrous membranes. The effect of electrospraying time and post electrospray processing condition of producing thin layer on the structure and functionality of the composite membranes was examined. The results showed that increasing the electrospraying time from 4 to 12 h enhanced formation of uniform coating on the surface of the nanofibers which resulted in lower permeability due to reduced pores size. Moreover, air flow was significantly decreased by increasing electrospinning and electrospraying time. The investigation of the efficacy of fabricated composite membranes for molecular weight cut off (MWCO) revealed that the MWCO was improved at prolonged electrospinning and electrospraying time and decreased diameter of the nanofibers. Furthermore, increasing water vapor treatment time from 10 to 60 min resulted in higher MWCO due to enhanced connection of PVA nanoparticles. Membrane fouling studies confirmed that the smaller diameter of the nanofibers and prolonged electrospinning time increased membrane fouling, while longer electrospraying duration enabled lowering fouling percentage. Finally, COD, BOD and turbidity was drastically reduced by 71.2%, 87% and 74%, respectively, using the optimized composite membrane for water-oil separation. Keywords : Thin Film Composite Membrane, Nano Fiber, Electrospining, Electrospray