A protocol was designed to evaluate babies in neonatal intensive care units by means of the auditory brain stem response (ABR) audiometric technique during their hospitalization. This article presents the results obtained from 200 babies. Twenty-three infants failed the ABR test. Fifteen babies were followed. Ten of these infants had significant sensorineural hearing loss. Three had unilateral involvement and seven had bilateral impairment. The seven bilaterally affected infants were fitted with appropriate hearing aid amplification and enrolled in audiologic habilitation programs. Continued follow-up of these babies has confirmed the hearing loss diagnosis. These data estimate that 5 percent of babies in neonatal intensive care units have some degree of hearing loss. The findings encourage the use of the ABR technique as a means of identifying hearing loss in the neonatal intensive care unit population.