A syntaxonomical analysis of the dry grasslands (Festuco-Brometea) in Bosnek karst region, Mt Vitosha (SW Bulgaria) has been carried out. These grasslands are part of the intrazonal vegetation distributed within the belts of xerophilous oak and mesophilous beech forest in the south-western foothills of the mountain. The bedrock is carbonate, the soils are dry and shallow, climate - moderate continental. This vegetation grows mostly on steep slopes, with southern and south-western exposition. Apart from the typical for Festuco-Brometea calcicoles, the studied vegetation is characterized by many endemic (regional and local) species and at the same time includes a lot of Mediterranean species. As a result of the analysis, a new association, Bromo moesiacae-Stipetum epilosae ass. nova, has been established that belongs to the alliance Saturejon montanae. A comparison with related syntaxa from other karst mountains from SW Bulgaria and E Serbia is made, and some conclusions about the origin of the steppe vegetation in that region are drawn.