Information on the occurrence of invasive species in towns of the Republic of Karelia is provided. In total, 47 invasive species have been recorded. The number of neophytes varies widely among towns – from 14 species in the youngest Town of Kostomuksha to 43 species in the largest City of Petrozavodsk. Invasive species have colonized all major types of natural and semi-natural biotopes occurring in towns of Karelia. The highest invasibility is characteristic of forests (including forest margins) and meadows; shores, banks, and rocky biotopes have somewhat lower invasibility; mires, aquatic and coastal habitats were invaded by two species each.