The perinatal histories of 16 preterm infants with confirmed moderate-to-profound hearing loss were examined to determine the perinatal factors that might have been associated with their abnormal auditory development. Of the 11 factors that were examined, eight factors occurred significantly more frequently in hearing-impaired infants when they were compared with 226 preterm infants who were cared for in the same intensive care unit in 1984. However, when the histories of the 16 infants with hearing loss were compared with those of 16 infants with normal hearing, who were matched according to gestational age, birthweight percentile and sex, there were no differences. The prevalence of aminoglycoside therapy was high in both groups of infants, but the mean duration of therapy in the infants with a hearing deficit was significantly longer (15 days compared with eight days; P less than 0.025). These observations suggest that younger, smaller, preterm infants with a complicated perinatal course and prolonged aminoglycoside therapy are at higher risk of auditory handicap. We recommend that the early identification of preterm infants with a hearing deficit should be achieved by recording brainstem auditory-evoked responses just before discharge from the intensive care unit.