Infectious diseases of childhood are endemic in large parts of the world and in particular, in developing countries, as well as in many indigenous communities and areas of low socio-economic status within developed nations. It is estimated that 3 to 4 million children less than the age of 5 years die each year due to diarrhoeal diseases and acute respiratory infections alone, annually. In addition, infections such as tuberculosis, hepatitis and human immunodeficiency virus also cause significant morbidity in children. Immunization is the most important public health intervention to improve child health in human history and during the 20th century it has resulted in a significant decrease in child mortality caused by infections. At present, vaccination prevents more that 2.5 million childhood deaths each year. However, despite these advances there remains a considerable burden of infectious disease in children globally. New vaccines need to be developed for a number of childhood infections for which there are none currently available or for which the current vaccines are not optimal. Issues still remain with respect to accessibility to vaccination either through a lack of political will, health infrastructure or affordable vaccine supply. In developed countries maintaining public compliance in national immunization programs when disease is not endemic is becoming a serious problem. The United Nations Millennium Declaration has as Goal 4 (MDG4) the reduction of child mortality- specifically by two-thirds in children less than five years of age by 2015. Vaccines are a key component of this MDG4 and whilst significant improvements in vaccine coverage have occurred globally, there still remain large variations in vaccine access between geographical areas. Rapidly advancing technologies will soon result in broader disease coverage, less invasive delivery systems and more affordable products that can be produced in developing countries. Furthermore, through a number of global initiatives to deliver vaccines to children, even in the poorest countries, there is promise that global immunization will continue to improve child survival and significantly reduce the burden of co-morbidities associated with infectious disease.