The large arionid slug Arion vulgaris (Gastropoda, Stylommatophora, Arionidae) is an invasive pest dispersing through large parts of Europe and causing considerable damage in gardens, horticulture and agriculture. Spanish slug is considered among the 100 worst alien species in Europe. It is a major agricultural pest, defoliator. The distribution of species in the urban environment of Nitra city was monitored at 18 study sites. Most adults occurred in summer, juveniles prevailed during early spring. Comparing data from monitored plots in Nitra (2015 and 2017); we found a significant decrease in the number of individuals depending on precipitation, precipitation significantly decreased in second year of research (by 70 mm). A comparison of the average values of the number of individuals in urban zones of the city revealed decreasing trend from the city centre to the suburban zone (outside the city). Occurrence of Arion vulgaris was concentrated in the central and peripheral zones, favouring habitats and microhabitats, respectively, in the immediate vicinity of humans.