Millennium Development Goal 4 (MDG 4) calls for reducing the under-five mortality rate by twothirds between 1990 and 2015. The world has made substantial progress, reducing the under-five mortality rate 47 percent, from 90 (89, 92) deaths per 1,000 live births in 1990 to 48 (46, 51) in 2012. However, this progress has not been enough, and the target risks being missed at the global level. To achieve MDG 4 on time, the global annual rate of reduction in under-five mortality rate would need to rise to 15.6 percent for 2012–2015, much faster than the 3.9 percent achieved over 2005–2012. At the country level, historical trends show that progress for most countries has been too slow and that only 13 of the 61 countries with high under-five mortality rates (at least 40 deaths per 1,000 live births in 2012) are currently on track to achieve MDG 4—with an average annual rate of reduction of 4.4 percent or more.