This is the first controlled prospective study of the effects of nicotine deprivation in adolescent smokers. Heart rate and subjective withdrawal symptoms were measured over an 8-hr period while participants smoked normally. Seven days later, participants were randomized to wear a 15-mg (16-hr) nicotine patch or a placebo patch for 8 hr, and they refrained from smoking during the session. Those wearing the placebo experienced a decrease in heart rate across sessions and an increase in subjective measures of nicotine withdrawal. Those wearing the active patch also reported significant increases for some subjective symptoms. Expectancy effects were also observed. The findings indicate that adolescent smokers experience subjective and objective changes when deprived of nicotine. As in previous research with adults, expectancies concerning the effects of nicotine replacement also influenced perceptions of withdrawal.