The effects of smoking on the function of frontal lobe in middle- and elderly-Japanese community dwellers were examined. The participants were 477 healthy individuals aged from 40 to 86 years old (the mean was 63 years old). The letter fluency test to measure verbal executive function and the D-CAT to measure information processing speed and sustained attention were used as the measures of cognitive function which reflects prefrontal cortex function. Analyses including age and years of education as covariates indicated that the intensity of smoking tended to influence digit cancellation performances and letter fluency performance. These findings suggest that smoking may exert a deleterious long-term effect on cognitive function.