The September 11, 2001 terrorist attacks (9/11) presented a unique opportunity to assess the physical health impact of collective stress in the United States. This study prospectively examined rates of physical ailments and predictors of health care utilization in a U.S. nationally representative sample over three years following the attacks. A sample of adults (N = 2592) completed a survey before 9/11/01 that assessed MD-diagnosed physical and mental health ailments. Follow-up surveys were administered at one (N = 1923), two (N = 1576), and three (N = 1950) years post-9/11 to assess MD-diagnosed physical health ailments (e.g., cardiovascular, endocrine) and health care utilization. Reports of physical ailments increased 18% over three years following 9/11. 9/11-related exposure, lifetime and post-9/11 stress, MD-diagnosed depression/anxiety, smoking status, age, and female gender predicted increased incidence of post-9/11 ailments, after controlling for pre-9/11 health. After adjusting for covariates (demographics, somatization, smoking status, pre-9/11 mental and physical health, lifetime and post-9/11 stress, and degree of 9/11-related exposure), increases in MD-diagnosed cardiovascular, endocrine, gastrointestinal, and hematology-oncology ailments predicted greater utilization of health care services over two years. After the collective stress of 9/11, rates of physical ailments increased and predicted greater health care utilization in a U.S. national sample.