Literature reviews have documented that exposure to trauma is related to adverse health outcomes across domains of self-reported health, morbidity, mortality, and utilization of health services (Friedman & Schnurr, 1995; Green &. Kimerling, chap. 2, this volume; Walker, Newman, & Koss, chap. 3, this volume). In this chapter we describe an integrative model that relates trauma to physical health through psychological, biological, behavioral, and attentional mechanisms. We use material presented in the preceding chapters to support the argument that posttraumatic stress disorder (PTSD) is the key mechanism through which trauma leads to poor health. We then discuss clinical, systems, and policy This chapter was coauthored by an employee of the United States government as part of official duty and is considered to be in the public domain. Any views expressed herein do not necessarily represent the views of the United States government, and the author's participation in the work is not meant to serve as an official endorsement.