The purpose of the study was to analyze hearing responses at 6- and/or 12-months old in infants who had been in the neonatal ICU, had normal results in hearing screening, but showed risk indicators for progressive and/or late-onset hearing loss. We assessed 100 infants, 60 at 6 months and 40 at 12 months, term and premature, who were enrolled for monitoring of auditory and language development at CEPRE/UNICAMP until their second year. The infants were evaluated by history; meatoscopy; behavioral assessment with musical instruments and verbal sounds; cochleopalpebral reflex; recognition of verbal commands; visual reinforcement audiometry; and tympanometry. The data revealed a high incidence of the responses expected for age ranges. However, there was incidence of responses indicative of conductive and sensorineural hearing loss or late hearing development. Evolution in skill responses to instrumental and verbal sounds and pure tones could be observed with increase of age. Therefore, it was concluded that the evolution of hearing responses could confirm the maturation process in the central auditory nervous system during the first year, and, taking into account the results indicating hearing loss and late hearing development, it was possible to identify the importance of intervention programs through specialist referrals and guidance for parents to minimize the consequences of hearing loss during infant development.