Using manualized abreactive Ego State Therapy (EST), 30 subjects meeting DSM-IV-TR and Clinician-Administered PTSD Scale (CAPS) criteria were exposed to either 5-6 hours of treatment or the Ochberg Counting Method (placebo) in a single session. EST emphasized repeated hypnotically activated abreactive "reliving" of the trauma and ego strengthening by the cotherapists. Posttreatment 1-month and 3-month follow-ups showed EST to be an effective treatment for PTSD. Using the Davidson Trauma Scale, Beck Depression II, and Beck Anxiety Scales, EST subjects showed significant positive effects from pretreatment levels at all posttreatment measurement periods in contrast to the placebo treatment. Most of the EST subjects responded and showed further improvement over time.