The following acoustic effects of incubators were investigated: Noise level and vibration measurements inside incubators. Noise emanation into the vicinity of incubators. Deadening of incubator noise by the hood. The noise intensity inside the incubators was also registered under conditions of intensive care using sound emitting therapeutic and monitoring equipment. The results show that the noise level of incubator motors can be tolerated. This applies to well-serviced incubators only, however. The hood muffles outside noise, particularly in the range of greatest hearing acuity. But there is no protection against noisy intensive-care systems within the incubator. The infants own noise production is considered to contribute substantially to the noise within an incubator.