In the 19th century smallpox vaccination was introduced into what are now called developing countries. In the 20th century both the range of available vaccines and immunization coverage increased considerably. In course of time the emphasis in immunization shifted from the containment of epidemics to their prevention. Vaccination technology also proved to be an instrument for the eradication or elimination of infectious diseases, with smallpox and polio as outstanding examples, although the initial optimism about this has become less. Presently, in immunization in developing countries emphasis is on routine vaccination of pregnant women and children, with occasionally a vaccination campaign in case there is or might be an epidemic. This picture will change significantly when a vaccine to prevent HIV becomes available to restrict the further transmission of HIV and as a consequence contain the HIV/AIDS epidemics that profoundly affect society in many developing countries.