Steppe-like habitats in Europe are seriously threatened as a result of fragmentation and anthropogenic degradation, at least in western and central parts. Considering the dramatic loss of steppe-like habitats, the evaluation of genetic variation in populations of steppe species is of immediate importance if appropriate conservation measures are to be undertaken. In this paper, we examine the genetic diversity of the highly endangered populations of the leaf-beetle Cheilotoma musciformis, which inhabits only a limited area in south-central Poland, which is geographically isolated from the continuous range of this species. Both mitochondrial and nuclear markers show that the Polish populations are distinct from Slovakian and Ukrainian ones. These regional populations should be considered independent conservation units. On the other hand, very little (mtDNA) or no (nuclear DNA) diversity has been found among the Polish subpopulations. This leads to the conclusion that this species has gone through a strong bottleneck leading to a drastic reduction in its genetic diversity prior to the establishment of present-day populations. Host plants have been identified for this species using barcodes, and the only hosts for the Polish and Ukrainian samples are sainfoins Onobrychis spp. while for the Slovakian sample it is either Dorycnium pentaphyllum or Lotus spp. (all Fabaceae). All of these data can be very valuable for the conservation of C. musciformis populations (e.g. for reintroductions).