Congenital cytomegalovirus infection occurs in about 1% of live births. Although symptomatic congenital infection often results in severe developmental deficits and mental retardation, about 90% have asymptomatic infection. Previous studies of the intellectual development in children with asymptomatic congenital cytomegalovirus have resulted in mixed findings. To control for the effects of hearing impairment (which occurs in about 15% of asymptomatic children) on intelligence scores, we tested 18 prospectively followed, normally hearing, school-aged children with asymptomatic congenital cytomegalovirus (15 black, ten male) and 18 controls matched for age, sex, race, school grade, and socioeconomic status. Children were tested via the Wechsler Intelligence Scale for Children-Revised, the Kaufman Assessment Battery for Children, and the Wide Range Achievement Test. Multivariate analysis revealed no differences between groups on intelligence scores or subscales, achievement scores, or incidence of learning disabilities (defined as significant discrepancy between intelligence and achievement), and mean scores for both groups were very close to national norms. It is concluded that the 25,000 children born in the United States each year with asymptomatic congenital cytomegalovirus and normal hearing are not likely to be at increased risk of mental impairment.