To provide a membrane/electrode assembly excellent in durability and capable of providing a high output voltage, and a process for its production.A membrane/electrode assembly 10 for a polymer electrolyte fuel cell, comprising a polymer electrolyte membrane 12; a first frame 14 disposed at the periphery of a first surface of the polymer electrolyte membrane 12; a second frame 16 disposed at the periphery of a second surface of the polymer electrolyte membrane 12; a first electrode 22 having a first catalyst layer 18 and a first gas diffusion layer 20; and a second electrode 28 having a second catalyst layer 24 and a second gas diffusion layer 26; wherein the inner edge portion of the is first frame 14 is located between the first catalyst layer 18 and the first gas diffusion layer 20; and the inner edge portion of the second frame 16 is located between the polymer electrolyte membrane 12 and the second catalyst layer 24. In its production, the first catalyst layer 18 is formed by applying a coating fluid containing a catalyst and an ion exchange resin on the first surface of the polymer electrolyte membrane 12, and then, the first frame 14 is disposed at the periphery of the polymer electrolyte membrane 12.