The use of the polygraph in German court proceedings has been made almost impossible by a large number of decisions over the last few decades. In contrast to developments in some neighbouring European countries, the German judiciary does not think much of the measuring device and it has been successfully banned from German courtrooms over the years for various reasons. This legal development is described in this article. On closer inspection, it becomes clear that underlying the rejection of the polygraph is the opinion that it cannot itself provide results that have a sufficiently scientifically based foundation for court proceedings. At the same time, this criticism also makes it possible to establish access for the polygraph to German courtrooms through targeted scientific research.