Descurainia sophia belongs to Brassicaceae family. It is a winter or spring annual weed. Flixweed used to be described as a ruderal weed, however, recently it has become, one of the main weed species in the cultivated plants. The aim of the present research was to determine the present state of flixweed occurrence in agrophytocenosis in the Lublin region. The research was connected with detailed observation of the agricultural crops cultivated in the Lublin region to determine places of flixweed occurrence. In the years 1997–2002, 90 phytosociological records were made with the Braun-Blanquet’s method. All observations were carried out every June and July. This research enabled to prepare the map of the occurrence of Descurainia sophia in the Lublin region. Also, cover coefficients of flixweed in different soil units and cultivated crops were calculated. In the Lublin region, Descurainia sophia occurred mainly in its eastern and south-eastern parts. It grows mostly in rendzinas (39% phytosociological records) and chernozems (38%p hytosociological records). Flixweed occurred mainly in winter sown crops such as wheat and rape. The fields with Descurainia sophia were localized near farms. However, Descurainia sophia was characterized by low cover coefficients and just for that reason it was not dangerous weed in the cultivated crops of the Lublin region.