A positive-reinforcement procedure was used to determine hearing sensitivity and noise-induced hearing loss in the chinchilla. The animals were reinforced with 45-mg pellets (Noyes) for depressing and holding a key for 1–6 sec and either releasing it during a 2-sec tone presentation or not releasing it during a 2-sec catch trial. Using a tracking procedure, thresholds were determined at 9–15 frequencies during each daily 1-h session. Following threshold determinations, two animals were exposed to a 123-dB-SPL band of noise (710–2800 Hz) for 15 min. Threshold shifts were measured daily after the exposure and the animals were sacrificed at 7 and 28 days post-exposure, respectively. Their cochleas were examined under the light microscope and the number of hair cells missing was compared with the hearing loss present. Contrary to previous findings, both animals showed a considerable permanent threshold shift that agreed closely with the degree of change seen in the cochlea. The advantages and disadvantages of the new behavioral procedure are discussed.