The aim of this study is to investigate the electrospinning of Nafion (R) nanofibers with poly(vinyl alcohol) (PVA) as a carrier polymer and to assess the thermal and chemical stability of resultant PVA/Nafion (R) nanofibers for the use in direct methanol fuel cells, in simulated conditions. Bead-free PVA/Nafion (R) nanofibers were produced using higher molecular weight PVA. Resultant PVA and PVA/Nafion (R) nanofibers were stabilized using two different methods which are BTCA crosslinking and thermal stabilization, followed by sulfonation of the PVA part. FT-IR analysis demonstrated that the membranes were stabilized and sulfonated successfully. Thermal, water, methanol and oxidative stability of the membranes were tested in addition to ion-exchange capacity. Morphological changes in the structure were analyzed using SEM analysis. Thermally stabilized PVA/Nafion (R) nanofibrous membrane was found to be stable against water, methanol and oxidative effects. The nanofibrous structure was well preserved after treatments, while the other membranes became a film-like material. Thermal stability of the PVA/Nafion (R) nanofibrous membrane was similar to that of commercial Nafion (R) 115 membrane up to 200celcius.