Two tests were made of the withdrawal-relief explanation of the improvements in performance obtained with smoking. Study 1 examined the extent to which abstinence from smoking produced poorer performance in smokers in comparison with non-smokers. No evidence was obtained of differences in performance in smokers who were deprived of cigarettes for 10 h and non-smokers. Study 2 tested smokers with a standard cigarette or sham smoking after one hour and 12 h of deprivation. There was no difference in performance for the two deprivation intervals either in the sham smoking condition, or after smoking the lit cigarette. This study gave no evidence for withdrawal-relief being an explanation of the improvements in performance obtained with smoking.