The United Nations Inter-agency Group for Child Mortality Estimation (IGME) was formed in 2004 to share data on child mortality, harmonize estimates within the UN system, improve methods for child mortality estimation and produce consistent estimates of child mortality worldwide for reporting on progress towards the Millennium Development Goals. IGME updates child mortality estimates annually, and this report presents the IGME’s latest estimates of under-five and infant mortality and assesses progress towards MDG 4 at the regional and global levels.