Rich structured landscapes with high proportion of semi-natural habitats including undisturbed ground are able to enhance the abundance of natural antagonists of pollen beetles (Meligethes spp.) and other oilseed rape herbivores. 30 circular landscape sectors with a radius of 2 km in an area 40 km east to Vienna were selected according to their landscape structure. The proportion of landscape elements such as crop area, oilseed rape area, grassland, herbaceous perennial area, fallows and wood dominated biotopes were mapped within the circular landscape sectors. In the centre of the mapped landscape sectors an oilseed rape field was situated wherein the impact of landscape structure on abundance and parasitisation of the pollen beetle was determined. With rising percentage and number of oilseed rape area less pollen beetles were found in the examined fields. High landscape diversity, shown by the Shannon- Index, as well as high percentage of wood- dominated biotopes that are hibernation sites of pollen beetles, enhanced the abundance of pollen beetles. High Mean Perimeter Area Ratio (MPAR) as well as a high percentage of fallows enhanced the abundance of pollen beetle- larvae. High percentage of oilseed rape fields and of fallows effected a rising tendency of parasitisation. Fallows may offer alternative food plants and hibernating sites for parasitoids and shall therefore, in view of reaching high parasitisation rates, be maintained or newly established.