Smal part (1100 ha-4,7 %) of the Landscape Park Pojezierze Iławskie is an agricultural area. On the arable soils of this area floristic and phytosociological studies of weed communities were performed. In total, 156 species of vascular plants were registered what makes 75 percent of the whole segetal population high diferentitation in field plants was found. Seven associations and three communities of segetal plants were distinguished. High quantitative participation of the field plant communities in the range of associations (72 percent studied areas) allows us to suggest that the degree of agrocenosis degradation is wery small in this area as compare to the majority of the agricultural areas in Poland. Taking into account floristical and ecological diferentiation, geographical range and syntaksonomical position three assiociations (Teesdaleo-Arnoseridetum minimae, Aphano-Matricarietum and Spergulo-Chrysunthemetum segeti) present high specific value and deserve of the active form of protection.