A population analysis of 1,474 non-related animals (563 Holstein, 548 Simmental, 168 Brown cattle and 195 crossbreeds) was carried out using 12 microsatellite markers. The real location of known individuals to their breeds of origin and the assignment of unknown individuals was tested. A STRUCTURE analysis of all individuals revealed three genetic clusters corresponding to three breeds while crossbreeds mostly clustered with Simmentals and to a lesser extent to Holstein. The assignment and Migrants Detection test was carried out using GeneClass. The results from the assignment test revealed that in purebreds >98% animals were assigned to the correct breed. The crossbreeds were assigned to Simmental (85%) and Holstein (15%) as expected. Individual assignment tests provided excellent assignment success in all three highly differentiated cattle breeds (FST between 0.076 and 0.095) and could prove very useful for numerous forensic applications.