Dracunculiasis (Guinea worm disease) is caused by Dracunculus medinensis, a parasitic worm. Approximately 1 year after infection from contaminated drinking water, the worm emerges through the skin of the infected person, usually on the lower limb. Pain and secondary bacterial infection can cause temporary or permanent disability that disrupts work and schooling. In 1986, the World Health Assembly (WHA) called for dracunculiasis elimination, and the global Guinea Worm Eradication Program, supported by The Carter Center, World Health Organization (WHO), United Nations Children's Fund (UNICEF), CDC, and other partners, began assisting ministries of health of dracunculiasis-endemic countries in meeting this goal. At that time, an estimated 3.5 million cases occurred each year in 20 countries in Africa and Asia. This report updates published and unpublished surveillance data reported by ministries of health and describes progress toward dracunculiasis eradication. A total of 542 cases were reported in 2012, compared with 1,058 in 2011. The disease remains endemic in four countries in 2013, but the overall rate of reduction in cases has accelerated compared with the first 6 months of 2012. In the month of January 2013, no cases were reported worldwide for the first time since the eradication program began in 1986. Failures in surveillance and containment, lack of clean drinking water, insecurity in Mali and parts of South Sudan, and an unusual epidemiologic pattern in Chad are the main remaining challenges to dracunculiasis eradication.