Experiential avoidance is a key factor in the development and maintenance of posttraumatic stress disorder (PTSD). Mindfulness-based interventions encourage nonjudgmental acceptance of thoughts, feelings, and experiences without avoidance. In a randomized trial that enrolled 116 veterans with PTSD, Polusny and colleagues compared mindfulness-based stress reduction with present-centered group therapy for treatment of PTSD. The authors report that compared with present-centered group therapy, mindfulness-based stress reduction resulted in a greater decrease in self-reported PTSD symptom severity during treatment and at 2-month follow-up, with the magnitude of symptom improvement suggesting a modest therapeutic effect. In an Editorial, Kearney and Simpson discuss treatment of PTSD.