Authorities estimate that 15-35 percent of Vietnam veterans meet diagnostic criteria for PTSD. According to the American Psychiatric Association, PTSD symptoms include an original encounter with a highly stressful event; a re-experiencing of the traumatic event; post-traumatic withdrawal from environmental interaction; and symptoms such as hyperalertness, sleep disturbance, and memory impairment. A thorough psychosocial history aids in differentiating PTSD from antisocial personality disorder. Clinicians must be careful to identify persons who may feign PTSD to obtain disability benefits or avoid criminal penalties. The literature provides considerable support for the use of group therapy with Vietnam veterans with PTSD symptoms. Feelings are more easily shared and guilts resolved in a group of persons who share combat histories. The author has conducted Vietnam veterans' groups in two correctional institutions. The multimodal groups have included educational, cognitive, and supportive components. For selected group members, individual sessions must occasionally supplement group therapy. 19 references.