AIDS is now the most serious threat to public health internationally, the US and Africa having the highest number of cases suffered so far. In the next century the situation is likely to deteriorate still further. In Sub-Saharan Africa, there could be 10 million infants with HIV and 10 million more who are AIDS orphans. This Wilton Park conference paper discusses the spread of AIDS and examines what action can be taken to inhibit its spread. It highlights the groups most seriously at risk and looks at the role of government and legislation in the fight against this deadly disease.