This study examined how treatment-seeking veterans with preexisting posttraumatic stress disorder (PTSD) (n = 178) were affected by vicarious exposure to the September 11 terrorist attacks. Participants were surveyed 0 to 5 months prior to 9/11 and resurveyed 6 months after the attacks. Half the patients reported that thoughts and feelings about 9/11 impaired their functioning some (37%) or most or all of the time (13%). However, there was little evidence that vicarious exposure to 9/11 altered the course of these patients' functioning. Mean symptom, substance use, and role functioning outcomes were unchanged from pre-9/11 levels. Time spent following media coverage of 9/11 events was weakly associated (r = .17 to .18, p < .05) with only two of eight functioning outcomes.