Morphometric skull variation was studied in Rhinolophus mehelyi, R. euryale and R. blasii by means of 50 cranial, mandibular and dental measurements. In R. euryale differences between age groups (subadults, adults and old adults) were not significant. Poorly pronounced sexual dimorphism (male skulls were, on average, larger than those of females in some measurements) and low geographical variability within Bulgaria were observed in R. euryale. We propose a simple biplot (length of cheek teeth against the rostral posterior width), a stepwise discriminant analyses of some criteria and numerical keys that allow the clear determination of crania or their parts. A large additional sample of incomplete crania was determined on the basis of these keys which, in turn, allow data to be obtained on species distribution patterns. Rhinolophus euryale is the most frequent and probably the most abundant horseshoe bat species examined, and occurs throughout Bulgaria. Rhinolophus mehelyi is widespread but appears to be relatively rare. Rhinolophus blasii is confined mainly to the southern regions of Bulgaria, but may be abundant locally.