Libythea celtis, earlier known as a southern European species, was recorded in the extreme southern regions of the Slovak Republic from the 1950s to 1980s. In the study period 1976- 1998, the species expanded northwards and it has been the most abundant in the southern part of central Slovakia, with single specimens also found in the central Slovak mountains. Temperature increase is considered to be one of the expansion factors in this case. Results of applied multiple regression model with weather parameters support certain relationship between current L. celtis abundance and average current and 2 years delayed summer temperature. These parameters explain 78% of variability in the model. Based on records, ecotone communities at lower elevations (up to 400 m a.s.l.) in the south part of central Slovakia, mainly in the Ipeľ river drainage basin, could be considered to be representative habitats of species occurrence at the moment. Other possible reason of L. celtis spreading northward (artificial planting of the host tree species – Celtis occidentalis and C. australis in Hungary and also in Slovakia) and potential migration routes of the species to Slovakia are also discussed.