Despite significant advances in individual treatment approaches for PTSD, knowledge of group approaches has lagged behind. Much of the reason knowledge about group treatment for PTSD has been limited is due to the complexity of conducting randomized controlled trials in the group treatment context. This limited empirical knowledge is unfortunate given the frequency with which group treatment for PTSD is used in clinical settings, including the Department of Veteran Affairs. The goal of this study is to examine the efficacy of a group cognitive-behavioral treatment (GCBT) for PTSD relative to group supportive counseling approach (i.e. group present centered treatment; GPCT). The sample consists of 196 veterans diagnosed with PTSD who are randomly assigned to either GCBT (n=98) or GPCT (n=98). Both treatments are administered by two therapists over the course of 14 sessions. Assessments take place at baseline, mid-treatment, post-treatment and 3-, 6-, and 12-month follow-up. The primary outcome measure is the PTSD symptom severity assessed with a semi-structured diagnostic instrument. Given the substantial rise of veterans presenting for PTSD treatment services, identifying an efficacious group treatment approach is invaluable.