Twenty-eight infants with asymptomatic congenital cytomegalovirus infection and 13 control infants were followed up prospectively. Congenital sensorineural hearing loss was documented by auditory brain-stem responses in four infected infants (two had mild bilateral loss, one had mild unilateral loss, and one had extreme unilateral loss) but in no controls. Four infected infants had diffuse periventricular radiolucencies on computed tomographic scan; none had calcifications or ventriculomegaly. No differences between groups were noted on neurologic examination results or on the Bayley Mental Developmental Index; however, one infected infant had a severely delayed Bayley Psychomotor Developmental Index score. In addition, the mean Mental Developmental Index score of the four infected infants with diffuse periventricular radiolucencies was significantly below that of the remaining infected infants (93 +/- 8 vs 109 +/- 13). These data suggest that asymptomatic congenital cytomegalovirus infection may be associated with a broad range of audiologic, subtle neuroradiologic, and neurodevelopmental differences in early infancy.