To provide an electrolyte membrane having high strength even if it is thin in the thickness, excellent dimensional stability even upon absorption of water and a low electrical resistance; a process for producing the electrolyte membrane; and a membrane-electrode assembly for polymer electrolyte fuel cells having a high output and excellent durability, having the electrolyte membrane. An electrolyte membrane which is made mainly of an ion exchange resin and reinforced with a non-woven fabric made of continuous fiber of a fluororesin wherein at least some of intersecting points of the continuous fiber are fixed, and which has, as the outermost layer on one side or each side, a layer not reinforced, made of an ion exchange resin which may be the same as or different from the above ion exchange resin. The non-woven fabric is produced by a melt-blown method.