Pneumonia kills more children than any other illness – more than AIDS, malaria and measles combined. Over 2 million children die from pneumonia each year, accounting for almost 1 in 5 under five deaths worldwide. Yet, little attention is paid to this disease. This joint UNICEF/WHO report examines the epidemiological evidence on the burden and distribution of pneumonia and assesses current levels of treatment and prevention. It is a call to action to reduce pneumonia mortality, a key step towards the achievement of the millennium development goal on child mortality.