Wisconsin Card Sorting Test (WCST) performance was assessed in 24 heavy smokers and 12 nonsmokers recruited from universities in the United States and Japan. Half of the smokers performed the WCST after abstaining from tobacco for 12 hr, whereas the remaining smokers smoked a cigarette of their preferred brand immediately before the test. Nonsmokers did not smoke. The WCST was administered by computer, first with standard instructions and then a second time with abbreviated instructions that specified the 3 sorting criteria. Results from the second run indicated that abstinent smokers made significantly more perseverative responses and errors than did nonsmokers or smoking smokers. Results expand on previous findings of effects of smoking deprivation on human cognitive performance.