This study compared treatment outcome at discharge, and 4, 8, and 12 month follow-up between an inpatient program consisting of a mixture of Vietnam combat veterans with posttraumatic stress disorder (PTSD) and general psychiatric patients (N = 42), and the same program at a later period, consisting of only Vietnam combat veterans with PTSD (N = 33). Veterans rated the homogeneous environment higher in satisfaction, support, order, clarity, and amount of discussion of combat, and lower in hostility, than the heterogeneous condition. However, veterans showed no improvement in condition at 12 month follow-up, with the exception of decreased violence, replicating earlier studies. No differences in outcome were found between homogeneous or heterogeneous treatment environments. This study underscores the enduring nature of chronic posttraumatic stress disorder in the veteran population.