One important reason for udder damages may be the wrong positioning of the milking unit, leading to the teats being pulled by different forces. For this reason the German Agricultural Society has developed a test machine, making it possible to measure four forces at the teats. To examine the influence of the resulting forces caused by different udder formations and differences between the milking systems, three udder formations were tested using different makes of automatic milking systems (AMS) and conventional milking systems (CMS). Wrong positioning of teat cups was ascertained in both systems. In CMS this was influenced mainly by the milker and the flexibility of short milk tubes, and in AMS mainly by tube guiding and reliable working techniques.