The study was designed to find a response on the behavioral level that would be an effective index across subjects for determining when conditioned aversive suppression of a response had been achieved. Ten male volunteers received shock during trials in which they had to smoke. Half of the subjects received a brief but more intense shock when they stopped smoking during a trial. A comparison of these subjects to the others showed their average amount of smoking suppression in pre- and post-treatment rates to be significantly (P < .025) greater. In addition, these subjects showed conditioned emotional responding. It was concluded that this behavioral level response was an effective index for determining when suppression of smoking would occur.