The preparation and characterization of membranes of poly[2,5-benzimidazole] (ABPBI) by spray casting at room temperature from an ethanol solution is described. The prepared membranes doped with 11 M H 3 PO 4 sorbed 1.5 molecules of acid per imidazole ring exhibiting a proton conductivity of 0.05 S • cm −1 at 153 • C. The 80 μm thick, homogeneous, membranes obtained were used for the preparation of a membrane electrode assembly (MEA). Fuel cell test conducted with the prepared MEA at temperatures between 100 and 180 • C shows an increase in the performance with temperature, with a maximum power density of 200 mW • cm −2 at 180 • C. The described ABPBI membrane preparation method from an ethanol solution at low temperature opens a simple route for overcoming the processability problems of the aforementioned polymer.