Congenital cytomegalovirus (CMV) infection is the major infectious cause of sensorineural hearing loss (SNHL) in children and is found in about 1 percent of infants born in the United States. Hearing loss may be apparent at birth or may be delayed and is of varying severity. Universal screening of newborn infants is an attempt to lower the age at detection so that intervention can begin by 6 months of age. This study, in a predominantly black and urban population, evaluated 388 children born at one hospital in the years 1980 through 1996 who were diagnosed in the newborn period as having congenital CMV infection. Routine audiological assessment began at age 3 to 8 weeks at the first clinic visit and was repeated at ages 6 and 12 months and then annually. Hearing loss was defined as thresholds of ≥21 dB and sensorineural loss as an air-bone gap of <10 dB.Only 17 percent of infants were screened before being discharged from the nursery. Suspected congenital CMV infection was by far the most common indication. The prevalence of SNHL at birth was 5.2 percent, and late-onset hearing losses continued to occur through the first 6 years of life. By age 6, the cumulative incidence of SNHL was 15.4 percent. The risk was greatest in children who had symptomatic disease at birth. Hearing loss became worse in nearly half of the children with SNHL recognized either at birth or later. Approximately one third of affected children had a fluctuating hearing loss. Just over 8 percent of children had hearing loss with thresholds of 30 dB or higher by age 6 years. At this time, 36 percent of children with symptomatic CMV infection and 11 percent of those who were asymptomatic had SNHL.Universal screening of newborn infants for SNHL secondary to congenital CMV infection may lower the age at detection in some cases but will not solve the problem of children who develop late-onset hearing loss that still may impair the development of speech and language.J Pediatr 1999;135:60–64