The current state of knowledge on the viral hemorrhagic fevers that infect man, namely smallpox, chikungunya fever, dengue fever, Rift Valley fever, yellow fever, Crimean hemorrhagic fever, Kyasanur Forest disease, Omsk hemorrhagic fever, Argentinian hemorrhagic fever (Junin virus), Bolivian hemorrhagic fever (Machupo virus), Lassa fever, hemorrhagic fever with renal syndrome, and Marburg and Ebola virus diseases are reviewed.