Psychophysical tuning curves were obtained on normal chinchillas using a shock-avoidance technique. Curves were measured at several levels and frequencies of the signal, and both simultaneous and forward masking were employed. The chinchilla curves were similar to those obtained with human subjects by other researchers. A comparison of the chinchilla psychophysical tuning curves with cat physiological tuning curves showed that the 2 were similar in shape and shapness of tuning.