Combat exposure is a consistent predictor of posttraumatic stress (PTS). Understanding factors that might buffer the effects of combat exposure is crucial for helping service members weather the stress of war. In a study of U.S. Marines returning from Iraq, hierarchical multiple regression analyses revealed that unit cohesion and combat exposure predicted PTS, depression, and anger. Furthermore, results indicated that unit cohesion may be an important buffer, possibly limiting the development of PTS and depression following combat exposure.