Operation of a liquid-fed Direct Methanol Fuel Cell (DMFC) working at 145 degrees C was demonstrated by using a composite membrane made of Nafion(R) ionomer and silica. The enhanced humidification conditions of the membrane-electrode (M&E) assembly allowed taking advantage of the high operation temperature with consequent speeding up of the methanol oxidation kinetics. A peak power density of 240 mW/cm(-2) for an oxygen-fed cell was reached; the measured methanol cross-over rate was 4 X 10(-6) moles min(-1) cm(-2). A physico-chemical characterization of the cell components is also reported.