Abstract: The HIV/AIDS epidemic continues to have a devastating effect on people in Africa especially those in the Sub-Saharan Africa. Over 34 million people living in Sub-Saharan Africa had been infected with HIV with more than 12 million of these already dead. It has been shown from the natural history of HIV infection that it is usually lethal to those infected by it. Factors suggested to affect the duration of clinical history include genetic susceptibility, viral load, concurrent infections and pre-existing immune status at the time of HIV infection. Based on available data, the survival time of HIV-infected persons is much shorter in Africa than in those in western countries. Many of the persons infected in Africa have poor access to a health care system; other infections such as tuberculosis combined with poverty and malnutrition seem to be playing important roles in the epidemiology and pathogenesis of HIV. In this study, the epidemiology, the biology and pathogenesis of HIV is examined.