Objective: The purpose of this study was to determine predictors of posttraumatic stress disorder (PTSD) in health care workers exposed to a disaster, in order to facilitate early case identification and prevention of subsequent morbidity. Method: Following nn air disaster; 355 military medical health care workers were studied over all 18-month follow-up period. Measures included assessment of peritraumatic reactions associated with the disaster, the frequency of other stressful events after the disaster, aid standard PTSD rating scales at 6, 12, and 18 months. Results: Multivariate logistic regression of data on health care workers who cared for victims of the air disaster showed that PTSD tons more likely to develop in those who had not completed college, those who had worked with burn victims, those who had experienced more stressful life events in a period of approximately 6 months following the disaster, and those who experienced emotional numbness immediately after the disaster. Conclusions: Results suggest that lower levels of education, exposure to grotesque bunt injuries, stressful life events following exposure, and feelings of numbness following exposure are useful predictors of subsequent development of PTSD.