This preliminary study assessed the impact of a 12-session aerobic exercise program on symptoms of Posttraumatic Stress Disorder (PTSD), anxiety, and depression. Overall results show no symptom reduction during baseline phases but significant reductions in PTSD, anxiety, and depression following the exercise intervention. Reductions were maintained during a 1 month follow-up. Results suggest that exercise programs may be valuable resources for managing treatment-resistant participants with PTSD and may also have a beneficial effect on anxiety and depression.