Background: The cognitive factor of Anxiety Sensitivity (AS; the fear of anxiety and related bodily sensations) is theorized to play a role in cannabis use and its disorders. Lower-order facets of AS (physical concerns, mental incapacitation concerns, and social concerns) may be differentially related to cannabis use behavior. However, little is known about the impact of AS facets on the immediate antecedents of cannabis use. Methods: This study used ecological momentary assessment (EMA) to prospectively examine the relations between specific facets of AS, cannabis craving, state anxiety, and cannabis use in the natural environment using real-world data about ad lib cannabis use episodes. Participants were 49 current cannabis users (38.8% female). Results: AS-mental incapacitation fears were related to significantly greater severity of cannabis-related problems at baseline. During the EMA period, AS-mental incapacitation and AS-social concerns significantly interacted with cannabis craving to prospectively predict subsequent cannabis use. Specifically, individuals with higher craving and either higher AS-mental incapacitation or AS-social concerns were the most likely to subsequently use cannabis. In contrast to prediction, no AS facet significantly moderated the relationship between state anxiety and cannabis use. Conclusions: These findings suggest facets of AS (mental incapacitation and social fears) interact with cannabis craving to predict cannabis use. Findings also suggest differential relations between facets of AS and cannabis-related behaviors. Depression and Anxiety, 2011. © 2011 Wiley-Liss, Inc.