The preponderance of experimental evidence gathered over the past three decades indicates that exposure to intense noise can lead to a wide variety of functional and structural changes in laboratory animals. Although little information regarding noise effects at more moderate levels is available, the range of intensities at which such effects begin to be manifested in humans seems to be present in animal quarters. Fortunately, there is an assortment of techniques for reducing the noise exposure of both animals and animal care personnel. Because of serious deficiencies in our knowledge concerning actual long-term noise levels in animal housing facilities and the ways in which such noise affects different species, the imposition at this time of quantitative regulations governing exposure limits for laboratory animals would be premature.