Tick-borne encephalitis (TBE) is one of the most important arboviral diseases across Eurasia. TBE virus (TBEV) is transmitted by tick bite and causes a potentially fatal neurological infection in humans. In the Russian Federation, TBE is endemic in most regions, with 3000-5000 cases of the disease annually. To characterise TBEV in Eastern Siberia, the complete genomes of five TBEV isolates from patients with different clinical manifestations were sequenced. The results show that the Siberian and Far Eastern subtypes of TBEV cause the disease in people in Eastern Siberia. Complete genome analysis revealed an unexpectedly high genetic variability within the Siberian subtype.