Langer's theory of mindfulness proposes that a mindful person seeks out and produces novelty, is attentive to context, and is flexible in thought and behavior. In three independent studies, the factor structure of the Langer Mindfulness/Mindlessness Scale was examined. Confirmatory factor analysis failed to replicate the four-factor model and a subsequent exploratory factor analysis revealed the presence of a two-factor (mindfulness and mindlessness) solution. Study 2 demonstrated that the two factors assessed discrete constructs and were not merely products of acquiescence. Support was also found for a nine-item, one-factor model comprised solely of mindfulness items. On comparing models, Study 3 suggested the superiority of the one-factor mindfulness model. Finally, a preliminary investigation of the concurrent validity of the revised nine-item Langer Mindfulness/Mindlessness Scale is presented. The current article offers researchers a revised version of a mindfulness measure derived from a cognitive perspective. (Contains 2 notes and 9 tables.)