The invention relates to a method for producing a plastics material article, said method including the extruding of a tube-shaped parison and the re-forming of the parison into a hollow body within a blow mold by applying differential pressure. The method includes initially a first expanding and partial shaping of the parison with the blow mold not completely closed. Then at least one opening is provided on the circumference of the pre-expanded parison. In a further step at least one part to be built-in is introduced through the opening into the interior of the partially shaped plastics material article. In a final step the blow mold is closed completely and the blow molding of the plastics material article is completed.