Mortality rates of children less than 5 years old range from <10 per 1000 live births in industrialized countries to >100 in the world's poorest countries. The fact that in New York City infant mortality fell from approximately 140 deaths per 1000 live births in 1900 to <60 per 1000 by 1930 indicates what can be achieved through improvements in public health, such as the provision of clean piped water, sewage disposal and fresh refrigeration. For children living in impoverished conditions today, excess mortality is largely due to infectious diseases for which there are effective vaccines. Thus, certain specific vaccines can reduce mortality and morbidity, improve quality of life and contribute to economic development. However, because many vaccines and the means to deliver them are beyond the financial resources of countries with the highest childhood mortality rates, strategies have been devised to provide vaccines to the most needy populations. These strategies include initiatives by the Global Alliance for Vaccines and Immunization, the International Finance Facility for Immunization and the Advanced Market Commitment, which together with various governments, international agencies and charitable foundations are providing funds to make life-saving vaccines available to the world's most needy children.