‘The emergence and state of the HIV and AIDS epidemic’ outlines the emergence of HIV/AIDS, charting the current state of the disease globally. Acquired Immunodeficiency Syndrome (AIDS) is caused by the Human Immunodeficiency Virus (HIV) virus. The spread of AIDS is a complex, long-wave, epidemic event, with waves of spread followed by waves of impact. The future of HIV/AIDS is, epidemiologically, reasonably predictable. Unless the virus mutates and becomes more easily transmitted it will be contained. Science is advancing, with new treatments becoming available and technological prevention methods, microbicides, and vaccines in the pipeline. The impacts are less certain, but will be confined to the worst affected countries and most marginal groups.