The invention relates to a method for the injection molding of a body having at least one wall portion covered on the outside by a label, that comprises: a) using a molding assembly (50) including two mobile parts, one of which at least includes a cavity for making said wall portion; b) using a pick-up means (10), a transfer means (20) and a deposition means (29) for the labels; c) actuating said transfer means so that the label is brought to the cavity and depositing said label in said cavity; d) removing said transfer means, and closing the molding assembly in order to proceed with molding; characterized in that it comprises using a machine including: A) a rotary platen (60) for supplying a plurality of work stations, and on which the molding assembly is mounted; B) an injection press provided at a work station, the molding assembly arriving in a closed and locked configuration at the station and being pressed against said injection press in order to fill the chamber; C) said transfer means (20) at an upstream station.