By January 2012, 23 years after the Global Polio Eradication Initiative (GPEI) was begun, indigenous wild poliovirus (WPV) transmission had been interrupted in all countries except Afghanistan, Pakistan, and Nigeria. However, importation of WPV into 29 previously polio-free African countries during 2003-2011 led to reestablished WPV transmission (i.e., lasting >12 months) in Angola, Chad, Democratic Republic of the Congo (DRC), and Sudan (although the last confirmed case in Sudan occurred in 2009). This report summarizes progress toward polio eradication in Africa. In 2011, 350 WPV cases were reported by 12 African countries, a 47% decrease from the 657 cases reported in 2010. From 2010 to 2011, the number of cases decreased in Angola (from 33 to five) and DRC (from 100 to 93) and increased in Nigeria (from 21 to 62) and Chad (from 26 to 132). New WPV outbreaks were reported in 2011 in eight African countries, and transmission subsequently was interrupted in six of those countries. Ongoing endemic transmission in Nigeria poses a major threat to the success of GPEI. Vigilant surveillance and high population immunity levels must be maintained in all African countries to prevent and limit new outbreaks.