Attachment theory is applied to understanding and treatment of (he anxiety condition of post-tiaumalic stress disorder in adults. Conceptualized as intensified attachment behavior which is elicited at separation or loss or threat of separation, PTSD responses represent an inherent, though exaggerated, attempt to ensure protection and security. The secure base of a therapeutic relationship reduces the intensity of responses and provides an opportunity to review experiences relevant to current distress in order to affirm emotional reactions and come to terms with distressing events. Implications for prevention are discussed.