Healthy undergraduates high (n = 27) and low (n = 27) in experiential avoidance underwent twelve 20 s inhalations of 20% carbon dioxide-enriched air, while physiological (e.g., skin conductance, heart rate, EMG, and end-tidal CO[subscript 2]) and subjective (e.g., subjective units of distress, evaluative ratings, number and severity of panic symptoms endorsed) reactions were continuously monitored. Individuals high in experiential avoidance endorsed more panic symptoms, more severe cognitive symptoms, and more fear, panic, and uncontrollability than their less avoidant counterparts. Magnitude of autonomic response did not discriminate between groups, nor were the observed effects accounted for by other risk factors for challenge-induced panic such as anxiety sensitivity. Results are discussed in terms of the pathoplastic relation between emotional avoidance and exacerbation of unpleasant emotional responses and the view that emotional avoidance may constitute a risk factor in the development and maintenance of anxiety disorders.