Aminoglycoside antibiotics, commonly prescribed for adults and children to treat a wide range of bacterial infections, are potentially ototoxic, often causing irreversible damage to the auditory and vestibular systems. Ototoxic hearing loss usually begins at the higher frequencies and can progress to lower frequencies necessary for understanding speech. Individual susceptibility to aminoglycoside ototoxicity is determined by multiple physiologic and genetic factors. Children are especially vulnerable to ototoxic-induced damage, which can affect speech and language development even when limited to the high frequencies. Monitoring hearing loss during and after treatment by conventional and ultra-high frequency audiometry allows early detection of ototoxic hearing loss. Objective measures such as auditory brainstem responses (ABRs) and otoacoustic emissions (OAEs) can provide information about auditory function for individuals unable to provide reliable behavioral data, including young children. Early detection and subsequent alteration of treatment, as well as the potential future use of otoprotectants, may minimize or prevent ototoxic hearing loss.