The rate of response of single fibers in the cat auditory nerve to tone bursts was measured prior to and following 1‐min exposure to a tone at the fiber's characteristic frequency. Measurements were made for several levels of the exposure tone. Ten test bursts, at near threshold levels, preceded exposure and 90 followed it. In some runs the test bursts were omitted so that the recovery of spontaneous activity could be studied. The last postexposure burst was followed by a silent period of at least 80 sec before the next test. Following exposure, response rate to the test bursts was less than the pre‐exposure value. Response rate recovered to at least 80% of the pre‐exposure level within 2–15 sec after exposure. Complete recovery of the rate to the pre‐exposure level occurred within 2 min. Both the amount of rate reduction and the time course of recovery could depend on exposure level. [Supported by the National Institute of Neurological Diseases and Stroke and the U. S. Air Force Office of Scientific Research.]