An Italian translation of the Infant Behavior Questionnaire-Revised (IBQ-R) was developed and evaluated with 110 infants, demonstrating satisfactory internal consistency, discriminant validity, and construct validity in the form of gender and age differences, as well as factorial integrity. Cross-cultural differences were subsequently evaluated for matched samples of Italian and United States (US) (N = 110) 3-12-month-olds. Across infancy, parents of US infants reported higher levels of activity, high and low intensity pleasure, and vocal reactivity, whereas Italian infants, particularly males, were rated higher on cuddliness. In early infancy only, US infants were viewed as higher on high intensity pleasure and perceptual sensitivity. (Contains 3 notes, 3 tables, and 3 figures.)