A new device presenting brief pulses of odorized air to human subjects was introduced for a study of olfactory evoked potentials. As a result, the response to skatole was the largest in the vertex region and consisted mainly of positive waves with a peak latency of 147.1 ±5.3 msec in normal non-smoking male subjects. These positive waves were distinguishable as evoked responses by the superimposing technique before averaging, and after averaging the positive response became evident. These present results showed the method of our olfactory measurements was effective for a clinical olfactory test.