Abstract: The process of preparing a middle ear prosthesis of polymeric material by injection moulding technology according to the presented invention is characterized by drying the thermoplastic polymer granules, preferably high density polyethylene or polyamide or polysulphone, at a temperature in the range of 60 to 150° C. for a period of 2 to 8 hours. Subsequently granules are plasticized and then injected at a temperature between 180 and 400° C. into the mold heated to a temperature between 60 and 150° C. Then obtained moulder is cooled and in the final stage it is hermetically packed in a vacuum and sterilized. In addition, the granules of the thermoplastic polymer composite are used, obtained by addition of bactericidal additive introduced into the thermoplastic polymer granules, preferably a silver powder with a particle size from 15 to 100 nm, in an amount of 0.1-3 wt %.