The seeds of oilseed rape (Brassica napus L.) are used in large-scale production of one of the most health-promoting plant oils in the food industry, as well as for animal feed and biofuel production. Thus, increasing the yield of this crop is of crucial economic and ecological importance. However, conventional breeding programs are slow, laborious and time-consuming. Hence, along with the discovery of the possibility to apply CRISPR/Cas technology to edit plant genomes and to accelerate the breeding process, much effort has been put into applying this technology to study specific genes and biosynthetic pathways, especially in species with many gene copies such as B. napus. Here, recent improvements in generating CRISPR/Cas-induced mutations in the B. napus genome, delivering CRISPR/Cas reagents into oilseed rape plant cells, fast-checking the efficiency of targeted mutagenesis of CRISPR/Cas reagents, and oilseed rape transformation and regeneration procedures are described. Finally, new applications of CRISPR/Cas tools in oilseed rape precision breeding are discussed, focusing mainly on applications verified in field.