Abstract: Little is known about what factors contribute to posttraumatic stress disorder among military healthcare personnel during a deployment. Accordingly, the purpose of this study was to explore the association among demographic variables, psychological and occupational stressors, and protective resources with probable PTSD caseness and PTSD symptom severity in a sample of 1161 military healthcare personnel who were deployed to a combat hospital in Balad, Iraq, between 2004 and 2011. In this cross-sectional observational study, participants completed anonymous self-report measures while in theater. Results indicated that a model with reports of depression symptom and negative affect severity, and exposure to combat and futility stressors (i.e. stressors that service members do not feel fully prepared to manage) was associated with probable PTSD caseness (χ2 (17, N = 739) = 236.62, p < .001). The model explained approximately 63.6% of the variance in probable PTSD caseness. A hierarchical linear regression predicted PTSD symptom severity, adding gender and trainable stressors (i.e. stressors that service members feel fully prepared to manage) as independent variables to the variables above (F (17, 839) = 89.76, p < .001; adjusted R2 = .64). In deployed military healthcare personnel, depression and negative affect (e.g. dysphoria, anhedonia, anger) may be behavioral proxies for PTSD severity and when present with noteworthy exposure to combat and healthcare stressors may provide discernable information that peers and leaders can use to check-in to see what service members may need to recover confidence and competence, if applicable.