RNA viruses are notorious for their ability to quickly adapt to selective pressure from the host immune system and/or antivirals. This adaptability is likely due to the error-prone characteristics of their RNA-dependent, RNA polymerase [1, 2]. Dengue virus, a member of the Flaviviridae family of positive-strand RNA viruses, is also known to share these error-prone characteristics [3]. Utilizing high-throughput, massively parallel sequencing methodologies, or next-generation sequencing (NGS), we can now accurately quantify these populations of viruses and track the changes to these populations over the course of a single infection. The aim of this chapter is twofold: to describe the methodologies required for sample preparation prior to sequencing and to describe the bioinformatics analyses required for the resulting data.