Invasions of species into ecosystems lead to their transformation and in some cases to degradation. The spanish slug Arion lusitanicus Mabille, 1868 (Mollusca: Gastropoda: Stylommatophora: Arionidae) has been spread actively in Europe including some regions of Ukraine recently. This is a dangerous invasive species that causes significant damage to natural and agroecosystems. There is a lack of nformation on the distribution of the species in Chernivtsi region. Therefore, the aim of the work was to assess the current distribution and allocation of the boundaries of the secondary range of Arion lusitanicus sensu lato in Chernivtsi region. Data on the spread of A. lusitanicus in the region have been obtained from the website of the National Biodiversity Information Network UkrBIN, as well as collected in the field during 2016-2019 and by surveying residents of settlements of Chernivtsi region. Estimation of A. lusitanicus populations density in selected localities has been performed applying the method of total collection and direct in situ calculation with parallel estimation of habitat area. The mapping method in Quantum GIS was used to present the cartographic material. As a result, it has been found that A. lusitanicus was recorded for the first time from Chernivtsi region in 2011-2012 in the city of Chernivtsi (Rosha district) and in the Novoselytsia district. The uneven spatial distribution of A. lusitanicus mollusk colonies on the territory of Chernivtsi region has been shown: the maximum number of localities within urban settlements and the absence of species on alpine and certain steppe territories. It has been noted that the boundaries A. lusitanicus range in Chernivtsi region are confined to the territory with an altitude of 350 m above sea level and are transitive, indicating the active spreading of the species