The demand for a Solid Polymer Electrolyte Membrane (SPEM) for fuel-cell systems, capable of withstanding temperatures above 130°C, decreasing the electrode-catalyst loadings and reducing poisoning by carbon monoxide, has prompted this study. A novel, low-cost, highly conductive, nanoporous proton-conducting membrane (NP-PCM) based on a polytetrafluoroethylene (PTFE) backbone has been developed. It comprises a non-conductive nano-size ceramic powder, PTFE binder and an aqueous acid. Impregnation of the ceramic powder into the membrane substrate was carried out by sol-gel synthesis. The preparation procedures were studied and the membrane was characterized with the use of: PSD, SEM, EDS, DSC, FTIR and electrochemical methods. A non-optimized direct-methanol fuel cell (DMFC) with a 137 μm-thick membrane was assembled. It demonstrated 133 mW.cm-2 at 80°C, 0.05 atm. dry air (1.9 stoich Future study will be directed to optimizing the Membrane-Electrode- Assembly (MEA) preparation process and testing of both DMFCs and H 2-FCs at high temperatures. copyright The Electrochemical Society.