This study was designed to assess the effect of controlled deep breathing on smoking withdrawal symptoms. In two laboratory sessions, dependent smokers refrained from smoking for 4 h. During a deep breathing session, participants were instructed to take a series of deep breaths every 30 min. During a control session, participants sat quietly. Controlled deep breathing significantly reduced smoking withdrawal symptoms, including craving for cigarettes and negative affect (tense, irritable), while resulting in the maintenance of baseline arousal (wide awake, able to concentrate) levels. Furthermore, a history of heavy smoking was associated with greater increases in arousal during the deep breathing session. The results of this preliminary study suggest that controlled deep breathing may be useful for relieving symptoms of smoking withdrawal.