The SARS-CoV-2 genome has been sequenced and the data is made available in the public domain. Molecular epidemiological investigators have utilized this information to elucidate the origin, mode of transmission, and contact tracing of SARS-CoV-2. The present review aims to highlight the recent advancements in the molecular epidemiological studies along with updating recent advancements in the molecular (nucleic acid based) diagnostics for COVID-19, the disease caused by SARS-CoV-2. Epidemiological studies with the integration of molecular genetics principles and tools are now mainly focused on the elucidation of molecular pathology of COVID-19. Molecular epidemiological studies have discovered the mutability of SARS-CoV-2 which is of utmost importance for the development of therapeutics and vaccines for COVID-19. The whole world is now participating in the race for development of better and rapid diagnostics and therapeutics for COVID-19. Several molecular diagnostic techniques have been developed for accurate and precise diagnosis of COVID-19. Novel genomic techniques have helped in the understanding of the disease pathology, origin, and spread of COVID-19. The whole genome sequence established in the initial days of the outbreak has enabled to identify the virus taxonomy. Several rapid, accurate, and sensitive diagnostic methods have been developed; those are based on the principle of detecting SARS-CoV-2 nucleic acids in clinical samples. Most of these molecular diagnostics are based on RT-PCR principle.