Group-based exposure therapy (GBET) was field-tested with 102 veterans with war-related posttraumatic stress disorder (PTSD). Nine to 11 patients attended 3 hours of group therapy per day twice weekly for 16-18 weeks. Stress management and a minimum of 60 hours of exposure was included (3 hours of within-group war-trauma presentations per patient, 30 hours of listening to recordings of patient's own war-trauma presentations and 27 hours of hearing other patients' war-trauma presentations). Analysis of assessments conducted by treating clinicians pre-, post- and 6-month posttreatment suggests that GBET produced clinically significant and lasting reductions in PTSD symptoms for most patients on both clinician symptoms ratings (6-month posttreatment effect size delta = 1.22) and self-report measures with only three dropouts.