Abstract: Dengue Viruses (DENV) are the most common arboviral pathogens in tropical and subtropical regions of the world. Analysis of codon usage patterns of DENV can reveal much about the molecular evolution of the viruses. The codon usage patterns of 119 samples of DENV were analysed including the Relative Synonymous Codon Usage (RSCU) and Codon Usage Bias (CUB). The overall extent of codon usage bias is low in DENV. The codon usage patterns of the 4 serotypes of DENV are significant different indicating that the evolutionary genetics of them are independent. Compositional constraint is a significant factor that affects codon usage variation. Mutation pressure is the main factor in codon usage variation of these viruses. Furthermore, natural selection may play a role in codon usage pattern of DENV as well. However, more comprehensive analysis is needed for show the deeper characteristic of synonymous codon usage and other responsible factors of codon usage bias in DENV.