Detailed knowledge of habitat requirements is an essential prerequisite for efficient conservation of any endangered species. Despite the grain support beetle Aegosoma scabricorne (Cerambycidae) being one of the largest European beetles, and an endangered, disappearing, species in Central Europe, its bionomics remain relatively poorly known. A. scabricorne is known as a polyphagous species on broadleaved trees; thus, to investigate its habitat preferences 174 broadleaved trees (87 occupied and 87 unoccupied by the species) were surveyed in the area of southern Moravia (Czech Republic) in 2015. The species was found to be strongly associated with declining or freshly dead trees that are, preferably, further damaged (breakage of stem or primary branch, hollows, etc.) and it particularly thrives on large trees (diameter >50 cm). Surprisingly, stem exposure to the sun was shown to be an unimportant characteristic for this species. However, in this study the number of exit holes was significantly smaller on the shaded north-facing quarter of the stem. Our results suggest concrete conservation measures to support the species. We also suggest that this species may be used as an umbrella species for saproxylic beetles of European lowland forests.