Background: The phenomenon of compulsive hoarding, characterized by the acquisition of and failure to discard a large number of possessions, is increasingly recognized as a significant public health burden. Despite the magnitude of the impairment associated with this condition, empirical research is still in the nascent stages and many facets of the phenomenology, underlying vulnerability and risk factors for hoarding, are as of yet unknown. Method: The overall aim of the current investigation was to examine the association between hoarding behaviors and two potential vulnerability factors—anxiety sensitivity (AS) and distress tolerance (DT). In addition, we investigated the robustness of these associations as well as the interaction between the two hypothesized risk factors. Three studies (total N=745) involving independent nonclinical samples assessed hoarding, AS, DT, and relevant covariates using a range of measures. Resutlts: Findings revealed that AS and hoarding are significantly and robustly associated with one another beyond general depressive, anxiety, and nonhoarding obsessive–compulsive symptoms. Hoarding was also found to be associated with low DT. Consistent with prediction, AS and DT interacted such that DT may play a less important role among individuals with low AS. By contrast, low DT appears to increase vulnerability to hoarding symptoms among individuals high in AS. Results are discussed with regard to future research and treatment implications. Depression and Anxiety, 2009. Published 2009 Wiley-Liss, Inc.