Abstract: Exposure therapy for posttraumatic stress disorder (PTSD) is efficacious for treating patients with multiple traumatic events. However, individuals with PTSD with exposure to multiple traumatic events are theorized to experience differences in emotional reactivity and fear extinction processes compared to those exposed to a single traumatic event. Thus, there is concern that individuals exposed to multiple traumatic events respond to exposure therapy differently than individuals reporting a single traumatic event. This study examined the impact of trauma frequency on exposure therapy processes, including within-session habituation, between-session habituation, and treatment outcomes in a sample of male veterans and active-duty military with combat-related PTSD engaging in Trauma Management Therapy (N=81). Individuals in both groups demonstrated significant improvements in PTSD symptoms from pre- to post-treatment. Of primary interest, individuals presenting with multiple traumatic events and single traumatic events demonstrated similar within- and between-session habituation, length and number of exposure sessions, rates of fear activation, and symptom reduction. The only significant difference observed was slower within-session habituation during the first Trauma Management Therapy session for individuals exposed to multiple traumatic events compared to individuals exposed to a single traumatic event. Results indicate that PTSD resulting from multiple traumatic events are as responsive to exposure therapy as those whose PTSD was caused by a single event. These preliminary results suggest that clinicians can utilize evidence-based exposure therapies to treat veterans and military personnel with multiple traumatic event histories.