Within the research project 2122 of the Austrian Federal Ministry of Agriculture, Forestry, Environment and Water Management „Quality comparision of European seed mixtures for permanent grassland“ an examination of different seed mixtures on 8 different sites in Austria has been carried out. The trials were conducted by AGES (Austrian Agency for Health and Food Safety), the Agricultural Research and Education Centre Raumberg-Gumpenstein and by the Federal Government of Tyrol. The influence of different seed mixtures on the botanical development of the plant stands was examined during 3 years at 2 different intensities. Perennial, competitive and well adapted seed mixtures in terms of climate and site conditions as well as concerning intensity resulted in stable plant stands, which in the 3rd year of investigations showed a well balanced distribution of grasses, clover and herbs and a lower proportion of unsown species. In seed mixtures rich in Lolium species suited for favoured areas outside the mountains 21.3-47.6 % of unsown species occurred. The use of site-adapted seed mixtures is of highest priority, because this is the only way for specific species and varieties to exert their properties to a full extent. Only site adapted, high grade mixtures combined with optimal land management and harvesting techniques lead to dense swards and sustainable, high yielding plant stands and high forage quality.