Perhaps no single cause of birth defects and developmental disabilities in the United States currently provides greater opportunity for improved outcomes in more children than congenital cytomegalovirus (CMV). --Cannon and Davis. BMC Public Health 2005;5:70 Each year in the United States, thousands of children and their families are affected by congenital cytomegalovirus (CMV) infection. More children may be affected by congenital CMV than by other, better known childhood conditions, such as Down syndrome, fetal alcohol syndrome, and spina bifida. The Centers for Disease Control and Prevention (CDC) has formed a Workgroup on Congenital CMV, led by the National Center on Birth Defects and Developmental Disabilities and the National Center on Infectious Diseases. This report provides background on congenital CMV infection and describes the goals and activities of the workgroup for reducing the burden of sequelae of congenital CMV infection.