Previous research has demonstrated elevated mortality rates among Vietnam-era veterans with posttraumatic stress disorder, especially deaths resulting from nonmedical causes. However, information on the relative contribution of particular risk factors to increased mortality is limited. We used receiver operating characteristics methodology to identify patient-level characteristics that predicted 7-year mortality in 79,551 middle-aged, male, posttraumatic stress disorder-diagnosed outpatients seeking mental health treatment within the Veterans Affairs Health Care System between April 1, 1998 and September 30, 1998. Receiver operating characteristics models indicated that the strongest predictor of mortality was a recent history of medical hospitalization, followed by severity of medical diagnoses and presence of a substance disorder. Results highlight the importance of addressing comorbid medical illnesses and addictive disorders when caring for this population.