It has been reported that exposure to increased noise levels impairs wound healing in surgical patients and in rats. The purpose of the present study was to determine if exposure to noise stress would alter the biological function of neutrophils, macrophages, and lymphocytes, leukocytes that are involved in wound healing. Rats were exposed to 80 db of “rock” music for 24 hr, during which time the control animals were maintained in their usual environment. Leukocyte subpopulations were obtained and stimulated in vitro. Neutrophils and macrophages from noise-exposed animals secreted significantly less superoxide anion and interleukin-1 than cells from control animals. Lymphocyte function was not altered following noise stress. We conclude that short-term exposure of rats to noise stress alters some of the biological functions of leukocytes.