In a process for producing a hearing aid, comprising a housing made out, at least partially, of a metallic or ceramic part using powder injection molding technique (PIM) within the housing (1) at least one additional element (3) made out of a polymeric material is arranged for placing functional parts (5, 7, 13) within or at the housing (1) to reduce complexity of P parts and/or to compensate any tolerances due to the PIM process.