The effects of noise, in general, and music, in particular, on the behavior and welfare of animals in the laboratory deserve a great deal of empirical study. However, many laboratories must develop their current practices on the basis of sparse and conflicting data. With this commentary we seek to establish some of the factors that should be taken into account in deciding how to deal with sources of uncontrolled or deliberate sound and, specifically, in determining whether to play music in the laboratory. Views differ, however, the balance of evidence supports the use of quiet music during nonhuman animals' active periods, if this practice is introduced with an awareness of the risks to welfare and research.