The amphibians and reptiles occurring in Balgarka Natural Park (NP), are a representative sample of the lowland and middle mountain range herpetofauna of the Stara Planina Mountains. Here we present the first detailed and targeted mapping for the NP. The data were collected mostly in 2012–2013, mainly based on visual searches using the transect method; additionally we sampled using funnel-trapping and dip-netting for the aquatic species. We collected data for all 96 of the 2×2 km UTM squares of the NP. Based on 1155 observations we identified ca. 7673 individuals (including amphibian larvae), from 10 species of amphibians (~46% of the species diversity at the national level), from which 4 were salamanders (Caudata, ~50%) and 6 tailless amphibians (Anura, ~43%), and 13 species of reptiles (Reptilia, ~35%), including 3 turtles (Testudines, 75%), 5 lizards (Sauria, ~33%), and 5 snakes (Serpentes, 28%).