This study evaluated the efficacy of pregabalin augmentation of antidepressant treatment in patients with posttraumatic stress disorder (PTSD). Nine patients meeting Diagnostic and Statistical Manual, fourth edition criteria for PTSD who were on stable doses of antidepressants were treated open label with flexibly dosed pregabalin for 6 weeks. All patients were assessed with the Short PTSD Rating Interview, Montgomery–Asberg Depression Rating Scale, Patient Global Impression-severity, Visual Analog Scale-pain, and Sheehan Disability Scale at baseline and weeks 2, 4, and 6. Significant reductions were observed in all effectiveness measures from week 4 to the end of the study. In particular, the numerical improvement of the Visual Analog Scale-pain score was most robust (−53.4%, P=0.007). Pregabalin augmentation was effective and well tolerated during the study. Our findings warrant adequately powered, placebo-controlled clinical trials to confirm the usefulness of pregabalin augmentation of antidepressants in patients with PTSD.