Pulsatilla styriaca (P. halleri subsp. styriaca), up to now considered endemic to Styria within Austria, is reported as new for the Bulgarian flora. Earlier, it had been identified as P. halleri s. str. (P. halleri subsp. halleri) because it is clearly different from P. rhodopaea (P. halleri subsp. rhodopaea) distributed in Bulgaria. The only three populations situated in western Sredna Gora (W Balkan mts.) are small and have been monitored during the period 1998–2013. Population sizes are decreasing and the species thus endangered in Bulgaria. By morphological (phytographical) evidence, using features of traditional Pulsatilla taxonomy, the differences between the Bulgarian and Styrian populations of P. styriaca, in respect to the variation amplitude, proved to be negligible. This taxon, however, turned out to be conspecific with P. subslavica distributed endemically in Slovakia. This is demonstrated by a comparative survey of Slovak specimens attributed to this species and specimens of P. styriaca from Styria. Consequently, P. styriaca is no longer endemic to Styria and Austria but exhibits a highly disjunct distribution range covering western central Slovakia, eastern Austria (Styria) and western Bulgaria. Bulgarian, Slovakian and Austrian habitats of this species are compared und the conservation status is discussed.