Health anxiety is associated with reassurance-seeking behaviors, including persistent medical care utilization. The current study sought to identify targetable and underlying (transdiagnostic) factors that may influence the relationship between health anxiety and medical care utilization. We examined the role of both anxiety sensitivity (AS; fear of arousal-related sensations) and intolerance of uncertainty (IU; fear of the unknown) in the relationship between health anxiety and likelihood of utilization of general, specialist, and emergency care among 566 adults (Mage = 20.47, SD = 3.54, 79.9% female). A three-way interaction revealed that AS strengthened the association between health anxiety and likelihood of general medical care utilization within the context of higher, but not lower, levels of IU. Only the main effects of AS and IU were significantly associated with odds of emergency care utilization, and there were no significant predictors of odds of specialist care utilization. Future directions and clinical implications are discussed.