The present investigation examined the factor structure, internal consistency, and construct validity of the 16-item Anxiety Sensitivity Index (ASI; Reiss Peterson, Gursky, & McNally 1986) in a young adult sample (n = 420) from the Netherlands. Confirmatory factor analysis was used to comparatively evaluate two-factor, three-factor, and four-factor models of the anxiety sensitivity construct. Support was found for a hierarchical structure of anxiety sensitivity, with one global higher-order factor and four lower-order factors. Internal consistency for the global and lower-order factors of the 16-item ASI was adequate. Convergent and discriminant associations between the 16-item ASI and general mood and panic-specific variables were consistent with anxiety sensitivity theory. In addition, incremental validity of the anxiety sensitivity construct was established, relative to negative affectivity, for unexpected panic attacks and agoraphobic avoidance.