Rapeseed (Brassica napus L.) is the most important oilseed plant in Poland. Genetically modified (GM) rapeseed is planted on 18% of total rapeseed area in the world. The most frequent genetic modifications in rapeseed gave transgenic lines that are herbicide tolerant or have altered fatty acid composition. Coexistence of conventional and GM rapeseed is difficult due to several facts related to biology of this species. Contamination of rapeseed conventional varieties with rapeseed GM seems to be unavoidable during flowering time, harvest, storage and transport. For this reason monitoring of GM rapeseed in Poland is very important. At the moment no validated method is available for quantification of GM in rapeseed. Therefore development and validation of qualitative methods for rapeseed transgenic lines in routine food and feed analysis are necessary.