About 500 aphid species inhabit the arctic zone in Northern hemisphere. Current level of knowledge of aphid species composition is too different for certain arctic and subarctic regions. Due to numerous expeditions to the arctic region of Eurasia during the last years our knowledge of species composition of aphid fauna and its genesis has been deepened significantly. The aphid fauna of Chukotka is more similar to the fauna of North America than to that of Siberia and Europe. From the West to the East proportion of monoecious species is increased but species richness is decreased. Monophagous species are the most numerous among arctic aphids. In conditions when plant hosts are rare some aphids inhabit plants atypical for them, that can lead ...