The inventory of the alien Acari of Europe includes 96 species alien to Europe and 5 cryptogenic species. Among the alien species, 87 are mites and 9 tick species. Besides ticks which are obligate ectoparasites, 14 mite species belong to the parasitic/predator regime. Among these species, some invaded Europe with rodents (8 spp.) and others are parasitic to birds (2 spp). The remaining 77 mite species are all phytophagous and among these 40% belong to the Eriophyidae (37 spp.) and 29% to the Tetranychidae (27 spp.) families. These two families include the most significant agricultural pest. The rate of introductions has exponentially increased within the 20th century, the amplification of plant trade and agricultural commodities movements being the major invasion pathways. Most of the alien mite species (52%) are from North America, Asia (25%), and Central and South America (10%). Half of the ticks (4 spp.) alien to Europe originated from Africa. Most of the mite species are inconspicuous and data regarding invasive species and distribution range is only partially available. More research is needed for a better understanding of the ecological and economic effects of introduced Acari.