Gentamicin is a potentially ototoxic drug routinely used for treatment of life-threatening infectious diseases in neonatology. In study 1, of 8,333 children examined for hearing disorders, 134 (1.6%) had received previous treatment with gentamicin. Only eight (6.0%) suffered from various extents of sensorineural hearing impairment, and all eight had a history of other risk factors of hearing loss (e.g., perinatal asphyxia, acidosis, icterus gravis, or meningitis). In study 2, 30 children (mean age, 13.2 months) with normal hearing had received gentamicin during the newborn phase, and 30 healthy children of similar age without previous gentamicin treatment were examined for vestibular function. Neither in the number of spontaneous eye movements nor in the means of the nystagmus parameters of the rotatory test did the data show any significant difference between the groups. The results indicate that gentamicin in controlled therapeutic doses has a less ototoxic and vestibulotoxic effect in newborns than it does in older children or in adults.