The effects of transection of the tapezoid body upon the cat's ability to localize sound were investigated. Four cats were trained to localize pulses of broad‐band noise in a free‐field situation, and their thresholds for minimal detectable angle were determined. After transection of the trapezoid body, each animal was tested for retention of the localization habit. Two animals retained the localization habit and showed little or no loss in threshold for localization; the other two failed to retain the habit and were unable to relearn to localize. Other auditory tests on the latter two animals indicated that they could learn to respond to a sound signal and that they could learn to discriminate between tonal patterns (high‐low‐high versus low‐high‐low). Electrophysiological records, obtained from each cat after testing was completed, showed that evoked potentials could be obtained from auditory areas of the cerebral cortex when click stimuli were presented to the ear. A comparison of the anatomical evidence for animals that retained the localization habit and those that were unable to relearn suggests that the anterodorsal portion of the trapezoid body may be crucial for localization. [This research was supported by the National Science Foundation.]