Certain environmental factors in neonatal intensive care have attracted large interest and have been studied thoroughly. However, less attention has been paid to the noise level inside infant incubators. The present study of four different types of incubators revealed high sound levels of 70 to 80 dB sound pressure level (SPL) at 125 Hz. Some infants are nursed in incubators for weeks or months and thereby exposed to these noise levels for an undue period of time. It is suggested that the high noise levels in infant incubators should be considered a perinatal risk factor with regard to later hearing impairment. It deserves more attention as hitherto, especially with consideration to the construction of incubators, but also in follow-up studies of long-term sequelae after an abnormal perinatal period.