Objective.To determine the ability of cigarette-pack warning labels, of the minimum size required by the World Health Organization, to capture the attention of smokers and nonsmokers.Methods.In this study, 30 smokers and 30 nonsmokers completed a dot-probe task in which they simultaneously observed images of cigarette packs split in two: the top contained the cigarette brand and the bottom contained the warning label.During the task, brain activity was recorded through two event-related potentials of the negative-polarity type--the potential that occurs in the posterior-contralateral zone approximately 200 ms after a stimulus (N2pc) and the sustained posterior contralateral negativity (SPCN) response--which are indicators of early and sustained attention.Results.In both groups, a greater amplitude of N2pc and SPCN potentials was found for the part of the pack containing the cigarette brand.However, during the dot-probe task, reaction times were shorter for the warning label.Conclusions.These results suggest that, initially, attention is focused on the cigarette brand, and only then on the warning label.The inability of warning labels to capture early-phase attention decreases their effectiveness, especially in smokers.We suggest that warning labels be enlarged to facilitate increased attention response.