This chapter considers the cost-effectiveness of existing strategies for addressing the diseases of poverty promoted by the World Health Organisation (WHO) and other intergovenmental organisations and compares these to other possible strategies. It examines the UN's response to HIV/AIDS and malaria. The chapter looks at what might be done to tackle those diseases of poverty which have a lower political profile but nonetheless constitute a significant proportion of the disease burden of less developed countries – diarrhoeal diseases, acute lower respiratory infections and diseases associated with malnutrition. Leading public health experts are virtually unanimous in concluding that prevention is of paramount importance in the fight against AIDS. In tackling diseases of poverty such as malaria and HIV/AIDS, global public authorities such as the WHO have a track record of prioritising grandiose but unachievable schemes over more practical approaches. Billions of dollars have been spent in recent decades, with little discernible impact on mortality rates.