Background: In individuals with posttraumatic stress disorder (PTSD), 70-90 % have at least one comorbid non-PTSD disorder. Objective: This study tested several hypotheses to untangle comorbidity issues. Following McMillen et al. ("Compr Psychiatry" 43(6):478-485, 2002), we hypothesized that few non-PTSD disorders would arise following traumatic events in children with substantial PTSD symptoms. Second, Repeated Events victims would show more internalizing and externalizing problems compared to Single Event and Hurricane Katrina victims. Third, we aimed to replicate in young children the finding from older populations that exposure to multiple events, not the type of event, would predict severity of symptoms. These results would inform speculations that repeated and prolonged traumas produce greater symptom complexity. Methods: Children 3-6 years of age were recruited for three types of trauma: Single (n = 62), Hurricane Katrina (n = 85), and Repeated Events (n = 137), and assessed with caregiver reports from a diagnostic interview. Results: Overall, 95% of children who developed new non-PTSD disorders following traumas also had substantial PTSD symptoms. The Katrina and Repeated Events groups showed more diagnoses of oppositional defiant disorder compared to the Single Event group, but groups did not differ on PTSD, depression, anxiety, or attention-deficit/hyperactivity disorder. Cumulative number of events was the only significant predictor of PTSD symptoms, while type of trauma and total occurrences of traumas did not predict additional variance. Conclusion: These data provide empirical support for targeting interventions on PTSD following traumas and disasters. The homogeneity of outcomes across types of traumas provides little empirical support for speculations that repeated and prolonged traumas produce greater symptom complexity.