Abstract Viruses of Flavivirus genus are the causative agents of many common and devastating diseases, including yellow fever, dengue fever etc. so for proper development of efficient anti viral pharmaceutical strategies there is a need for proper classification of viruses of this group. To generate the most diverse phylogenetic datasets for the Flaviviruses to date, we analyzed the whole genomic sequences and phylogenetic relationships of 44 Flaviviruses by using various bioinformatics tools (MEGA, Clustal W, PHYLIP). We analyze these data for understanding the evolutionary relationship between classified and unclassified viruses and to propose for the reclassification of unclassified viruses which shows sequence similarity and also similar mode of transmission with classified viruses.