A growing body of evidence suggests that anxiety sensitivity (AS; fear of arousal-related sensations) plays a role in posttraumatic stress disorder (PTSD). Consistent with this, evidence indicates that interoceptive exposure (IE), which is a method for reducing AS, reduces PTSD symptoms. Clinical observations from our treatment studies indicate that IE triggers both anxiety and trauma memories in people with PTSD. The primary aim of this study was to describe the anxiety responses to a series of IE exercises and to examine whether or not trauma memories were activated. A secondary aim was to explore the relationships among AS, PTSD symptom severity, and IE responses. Data were collected from 23 people with PTSD who completed measures of PTSD symptoms and AS and a standardized battery of 10 IE exercises. Elevated anxiety and strong arousal responses were frequently elicited by the exercises, and trauma memories were also frequently triggered. AS and IE-triggered trauma memories significantly predicted IE-induced peak anxiety. The implications of the findings are discussed in terms of how IE might exert its therapeutic effects in the treatment of PTSD.