Untreated syphilis during pregnancy, especially early syphilis, can lead to stillbirth, neonatal death, or infant disorders such as deafness, neurologic impairment, and bone deformities. Congenital syphilis (CS) can be prevented by early detection of maternal infection and treatment at least 30 days before delivery. Changes in the population incidence of primary and secondary (P&S) syphilis among women usually are followed by similar changes in the incidence of CS. To assess recent trends in CS rates, CDC analyzed national surveillance data from the period 2003--2008. This report summarizes the results of that analysis, which indicated that, after declining for 14 years, the CS rate among infants aged <1 year increased 23%, from 8.2 cases per 100,000 live births in 2005 to 10.1 during 2008. That increase followed a 38% increase in the P&S syphilis rate among females aged >or=10 years from 2004 to 2007. During 2005-2008, CS rates increased primarily in the South (from 9.6 per 100,000 live births to 15.7) and among infants born to black mothers (from 26.6 per 100,000 live births to 34.6). Reversing the upward trend in CS rates will require collaboration among health-care providers, health departments, health insurers, policymakers, and the public to reduce syphilis among women and to increase early prenatal care access and syphilis screening during pregnancy.