To assess the psychometric properties of the Italian translation of the Barratt Impulsiveness Scale-11 (BIS-11), the scale was administered to 763 college undergraduates. Based on analyses using item-total correlations and t-tests for differences between the top and the bottom total score quartiles, all items from the English version of the BIS-11 were retained in the Italian version. Cronbach's α for internal consistency was .79 and two-month test–retest reliability was .89. An exploratory principal-components analysis replicated the six first-order factors and three oblique second-order factors, consistent with the number identified in the English version. However, subfactor item loadings differed between the English and Italian versions. The overall item pool was consistent in being a homogeneous measure of impulsiveness. The BIS-11 total score was correlated significantly with aggression and ADHD measures. The BIS-11 also significantly differentiated between high and low levels of binge eating, alcohol consumption, and cigarette smoking. © 2001 John Wiley & Sons, Inc. J Clin Psychol 57: 815–828, 2001.