The aim of this study was to investigate the influence of posttraumatic stress disorder (PTSD) on rehabilitation after severe traumatic brain injury (TBI). Ninety-six patients with severe TBI patients were assessed 6 months after hospital discharge with the Posttraumatic Stress Disorder Interview, the Functional Assessment Measure (FAM), the Community Integration Questionnaire (CIQ), the Overt Aggression Scale (OAS), the General Health Questionnaire (GHQ), the Beck Depression Inventory (BDI), and the Satisfaction with Life Scale (SWL). PTSD was diagnosed in 27% of patients. Patients with PTSD reported higher scores on the GHQ and BDI, and lower scores on the FAM, CIQ, OAS, and SWLS than those without PTSD. Effective rehabilitation after severe TBI may be enhanced by management of PTSD.