Each year, numerous bank robberies take place worldwide. Even so, only few studies have investigated the psychological sequelae of bank robbery and little is known about the risk factors associated with the development of posttraumatic stress disorder (PTSD) following this potentially traumatic event. Knowledge about risk factors related to PTSD may allow for preventive measures to be taken against the development of PTSD and reduce the large cost associated with the disorder. We investigated multiple predictors of PTSD severity in a highly representative Danish cohort study of bank employees exposed to robbery (N = 371, response rate = 73 %, dropout rate = 18 %). The results of a hierarchical regression analysis showed that 51 % of the variance in PTSD severity could be explained with only peritraumatic dissociation, acute stress disorder (ASD) severity, and negative cognitions about self being significant predictors. However, interpretation of the role of peritraumatic dissociation in the regression model was hampered by a statistical artifact. The results indicate that screening for PTSD following bank robbery should focus on ASD severity, and that it may be possible to develop preventive cognitive interventions targeted at bank employees that focus on changing negative cognitions about self.