Setting up extrusion lines for highly-filly compounds is a very challenging task since the raw materials – and in particular CaCo3 – oftentimes have differing quality aspects and material characteristics. The various raw materials, setup of the line components and parameters of the extrusion process itself open up a wide field of options - not just in terms of improving the final product, but in the worst case also in terms of making things worse. Thus the extrusion process is affected by many factors that need to be taken into account for achieving optimum product quality and a stable process of the extrusion line. With many years of experience in compounding highly-filled compounds, the paper offers a wide repository of good clues and ideas how to optimize extrusion lines and what aspects have to be taken into consideration to achieve an optimum layout of the extrusion line for such demanding compounding tasks.