Zika virus is an arthropod-borne virus and belongs to the Flaviviridae family. The virus is primarily transmitted through the bite of infected Aedes mosquitoes, but can additionally be transmitted from mother to child during pregnancy or around the time of birth. Although most Zika virus infections are subclinical, severe manifestations have been described, including Guillain-Barre syndrome in adults and microcephaly in newborns. The virus have originated in East Africa and subsequently spread in two directions - to West Africa and then to Asia. There are two genetic lineages of Zika virus, the African lineage and the Asian lineage. In this master’s thesis we compared two strains of the Zika virus: strain #976 that was isolated in 1947 from the blood sample of a monkey in Uganda, and strain 800/16 that was isolated in 2016 from the serum of a viraemic female patient who returned from Brazil and presented typical clinical symptoms of an infection with the Zika virus. We established that the cell line of a monkey kidney epithelial cells VERO E6, the cell line of a mosquito cells C6/36 and the cell line from the cells of a human neuroblastoma SK-N-SH support the growth of the studied virus isolates. The viral isolates caused a CPU on the cell lines VERO E6 and SK-N-SH, but not on the cell line C6/36. We also defined the nucleotide and amino-acid sequence of the complete genomes. We found out that Zika virus, strain #976, is one of the isolates of the prototype strain ZIKV MR766, that were isolated in 1947 in Uganda and belongs to the African lineage ZIKV. The 800/16 strain belongs to the Asian lineage and is very similar to the strains that caused an epidemic in South and Central America and in the Caribbean in 2015 and 2016.