15% of all human cancers worldwide are caused by viruses. The viruses that cause cancer contain either single-stranded RNA or double-stranded DNA genomes. RNA viruses include Human T lymphotropic Virus type 1 and Hepatitis C and DNA viruses are HPV, Human Herpesvirus-8, Epstein-Barr Virus, Hepatitis B Virus. All of these viruses are blood-borne pathogens and are transmitted via blood transfusions, sexual contact, and during parturition. Oncogenesis driven by viral proteins are easier to treat through targeted therapy and immunotherapy because the presence of viral gene products differentiates between normal cells and cancerous cells. Vaccination is recommended for prophylaxis and treatment of this kind of cancer in order to strengthen the immune system, stop viral replication, and inactivate the virus. Although virus-mediated tumorigenesis is slow, other factors can play an important role in cancer progression such as genetic factors, environmental factors, and immunosuppression. Below is the infectious viruses that lead to carcinogenesis in exposed individuals: