Object of study: Studies of lung helminths from various groups were performed. Elaboration of biological and taxonomic classification of these species has been proposed. Materials and methods: 16 species from families Cervidae, Bovidae, Leporidae and humans were studied for lung helminths in Russia (South and central), Armenia, Bulgaria, Poland. The helminths found were studied using a scope of traditional and elaborated helminthological methods. Results and discussion: In lungs of mammals studied 23 helminth species have been found including 1 of Taeniidae (Echinococcus granulosus), 4 of Dictyocaulidae and 18 of Protostrongylidae. We have divided species composition of these lung helminths into three biological groups. The first biological group included nematodes from Dictyocaulidae family. Life cycles of those helminths are monoxenous (they are geohelminths). The second group includes helminths from family Protostrongylidae. Their life cycles include intermediate hosts — land snails and so they are dixenous (biohelminths). The third group includes an agent of a quite dangerous zoonosis — Echinococcus granulosis larvae. These cestodes also develop per dixenous type, but their intermediate hosts are vertebrates with definitive hosts also vertebrate, mostly carnivores. Taxonomic classification for family Protostrongylidae haelminths is also proposed.