To test whether or not the pairing of two external stimuli during sleep could induce a change in a behavioral response during the waking state, we used a second-order conditioning procedure and subsequently tested its effectiveness in a lick suppression response. After lick training, waking rats underwent first-order conditioning with low-level electrotactile stimulation to the ear (ETS) signaling a footshock. On the following day, the animals were exposed while awake or asleep to second-order pairing with a tone signaling ETS delivery. They were subsequently tested for lick suppression to the tone. The results showed that animals that had received tone-ETS pairings during either paradoxical sleep or slow-wave sleep exhibited lick suppression to the tone. This response was less pronounced than that of subjects who had received pairing during waking. But it was strong enough to be maintained over all three test sessions, which attests to its reliability. The nature of the process that took place during sleep as a result of second-order pairing is discussed.